Different Concentrations Of Nanoparticles Research Articles

Numerical study of the use of shear-thinning nanofluids in a microchannel heat sink with different pin densities and including vortex generator

This article numerically investigates the thermal and hydraulic performance of shear-thinning nanofluids when used as heat-conducting fluids in a microchannel heat sink device. Five geometries are evaluated: four with different pin densities and one with vortex generators. Six Reynolds numbers are studied, ranging between 200 and 1200. Numerical experiments show a comparison of using a water/ethylene-glycol mixture with and without alumina nanoparticles and multiwalled carbon nanotubes. Two different concentrations of nanoparticles were evaluated, both given shear-thinning nanofluid behavior. The viscous properties of the fluids are fitted from previously reported experimental data. The other thermophysical properties are modeled using single-phase expressions adjusted to consider hybrid nanofluids. Numerical results show that the heat transfer rates and pressure drop increase when the pin density increases, resulting in thermal blocking in the case of higher pin density. These key findings are a result of the increase in the heat transfer of shear-thinning nanofluids and the reduction of the pressure drop when compared with Newtonian fluids. Apparent viscosity contours are used to understand the thermal and hydraulic performance. Between the two nanofluids studied, the one with the lowest power-law index was the best in terms of heat extraction and pressure drop, indicating that fluids with thinning rheology may be recommended for heat transport in microchannel heat sink devices.

A bibliometric and performance evaluation of nano-PCM-integrated photovoltaic panels: Energy, exergy, environmental and sustainability perspectives

One of the major problems regarding PV panels is the decline in power output and efficiency whilst exposed to temperatures surpassing their operating temperature. In order to preclude such undesirable situation, it is imperative to cool PV panels and provide a uniform distribution of surface temperatures during the implementation of the cooling method. Thermal management can be achieved at the surface temperatures of PV panels by utilizing phase change materials (PCMs). In this study, along with PCM, the potential of enhancing output parameters by decreasing the surface temperature of PV panels with the addition of nanoparticles (Al2O3) at different concentrations (0.05%, 0.1%, and 0.15% w/v) to PCM (RT35) is examined. The study compared five systems: a reference PV panel (PV), PV panel cooled with PCM without nanoparticles (PVPCM-0), and PV panels with PCM containing different concentrations of nanoparticles (PVPCM-0.05, PVPCM-0.1, and PVPCM-0.15). Among the five different systems, the PV panel containing 0.15% w/v nanoparticles (referred to as PVPCM-0.15) demonstrated the most effective cooling capability. Moreover, the PVPCM-0.15 system provided the highest performance with a 19.49% increase in panel power output. PV systems have average energy and exergy efficiency values of 9.06% and 3.79% for PV panel, 9.60% and 5.15% for PVPCM-0, 9.70% and 5.12% for PVPCM-0.05, 10.28% and 6.01% for PVPCM-0.1, and 10.44% and 7.29% for PVPCM-0.15. Upon analyzing the sustainability metrics, it was determined that the PVPCM-0.15 system was more energy and environmentally sustainable than the others.

Insights into the role of ionic surfactants on the morphology of gold and gold@silver nanoparticles

Cyanidin-3, 5-di-O-glycoside (anthocyanin) was extracted from the red rose flower petals in an aqueous media. Anthocyanin was used as reductant to the preparation of gold nanoparticles with cationic and anionic surfactants. UV–visible absorption spectroscope, transmission electron microscope, scanning electron microscope, and energy dispersive X-ray spectroscope were employed to determine absorption bands of anthocyanin, surface Plasmon resonance (SPR) band, and morphology of the gold and gold@silver nanoparticles. Anthocyanin exhibited two absorption peaks at 284 and 518 nm, and one shoulder at 328 nm in the UV–visible spectrum. The intensity of these peaks decreases with time after the addition of HAuCl4. The color and the position of SPR band of gold nanoparticles depend on the concentration of gold salt with and without cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS). The anionic and cationic head groups of SDS and CTAB micelles have significant impact of the morphology of gold nanoparticles. Seedless co-reduction method was used for the synthesis of gold@silver nanoparticles. TEM images clearly indicate the formation of bimetallic gold@silver core-shell nanoparticles. The antioxidant power of AuNPs and gold@silver nanoparticles were tested in terms of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity as a function of different concentrations of nanoparticles.

Synthesis, characterization and antimicrobial activity of Cassia fistula mediated Cobalt doped Copper oxide nanoparticle against Salmonella typhi a step toward antibacterial nanomedicine

Synthesis, characterization and antimicrobial activity of Cassia fistula mediated Cobalt doped Copper oxide nanoparticle against Salmonella typhi a step toward antibacterial nanomedicine

Effect of biotic and abiotic elicitors on Salvadora persica callus in vitro

The research was conducted to study the effect of different concentrations of nanoparticles (chitosan and titanium dioxide) of Fusarium oxysporum as elicitors to increase the production of active compounds from Salvadora persica callus. Determine the total flavonoids and alkaloids rustle that chitosan in 5 mg/L, titanium dioxide in 1 mg/L, and Fusarium oxysporum in 5 mg/L give 93.10 mg100mg, 128.7 mg/100mg, and 107.61 mg/100mg respectively whereas alkaloids give 2.39%, 3.91%, and 2.20 % respectively. The results showed superiority in the presence of flavonoids in the samples compared with alkaloids. HPLC (High-performance liquid chromatography) analysis shows significant differences in increasing flavonoid production (Rutin, Kaempferol, Quercetin, Catechin, Luteolin, and Apigenin) the addition of chitosan at 5 mg/L led to an increase in the production of Rutin, at 39.89mg/L. As for the induced callus treated with titanium dioxide at 1 mg/L, it increased Rutin to 35.89mg/L. While Rutin increased its production to 30.12 mg/L when treated with Fusarium oxysporum at 5 mg/l.

Characterization And Antimicrobial Activity of Copper Oxide Nanoparticles Synthesized by Crocus Sativus Extract

This study aimed to evaluate the antimicrobial activity of green synthesized copper-oxide nanoparticles (CuO-NPs) using Crocus sativus. The microorganisms were supplied from Baghdad Teaching Hospital. Using C. sativus, CuO nanoparticles were synthesized in a green manner, and their properties were assessed using UV-visible spectroscopy at the peak of 260 nm. Atomic force microscopy (AFM) was used to measure the particles' size and form, and x-ray technology was used to more precisely quantify their dimensions. diffraction (XRD). The biomolecule and functional group were determined by Fourier transform infrared spectroscopy (FTIR). Different concentrations of nanoparticles (50, 75, and 100 ?g/ml) were subjected to the well diffusion method for antibacterial activity testing. The findings indicated that the CuO-NPs had a spherical form and a 0.154 nm size. The average diameters of the AFM pictures were found to be 11.89 nm, 2.62 nm, and 24.55 nm. The following growth zone inhibition values for the various bacteria species used were revealed by the nanoparticles' antimicrobial activity results: Staphylococcus aureus 18 mm, Staphylococcus epidermidis 18 mm, Klebsiella ssp 15 mm, Candida albican 18 mm, and Escherichia coli 17mm.

Comparison of biosynthetic zinc oxide nanoparticle and glucantime cytotoxic effects on Leishmania major (MRHO/IR/75/ER).

Currently, zinc oxide (ZnO) particles are used in nanotechnology to destroy a wide range of microorganisms. Although pentavalent antimony compounds are used as antileishmanial drugs, they are associated with several limitations and side effects. Therefore, it is always desirable to try to find new and effective treatments. The aim of this research is to determine the antileishmanial effect of ZnO particles in comparison to the Antimoan Meglumine compound on promastigotes and amastigotes of Leishmania major (MRHO/IR/75/ER). After the extraction and purification of macrophages from the peritoneal cavity of C57BL/6 mice, L. major parasites were cultured in Roswell Park Memorial Institute-1640 culture medium containing fetal bovine serum (FBS) 10% and antibiotic. In this experimental study, the effect of different concentrations of nanoparticles was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) colorimetric method, in comparison to the glucantime on promastigotes, amastigotes and healthy macrophages in the culture medium. The amount of light absorption of the obtained color from the regeneration of tetrazolium salt to the product color of formazan by the parasite was measured by an enzyme-linked immunosorbent assay (ELISA) reader, and the IC50 value was calculated. IC50 after 24 h of incubation was calculated as IC50 = 358.6 µg/mL. The results showed, that the efficacy of ZnO nanoparticles was favorable and dose-dependent. The concentration of 500 µg/mL of ZnO nanoparticles induced 84.67% apoptosis after 72. Also, the toxicity of nanoparticles was less than the drug. Nanoparticles exert their cytotoxic effects by inducing apoptosis. They can be suitable candidates in the pharmaceutical industry in the future.

Green Synthesis of Silver Nanoparticles Using Drymaria cordata and Their Biocompatibility with Hemoglobin: A Therapeutic Potential Approach.

In this study, we present the synthesis and characterization of AgNPs using Drymaria cordata along with an assessment of their antioxidant, antibacterial, and antidiabetic activities. Antibacterial activities using four bacterial strains, free radical scavenging assays (DPPH and ABTS), and carbohydrate hydrolyzing enzyme inhibition assays were done to examine the therapeutic efficacy of AgNPs. Additionally, herein, we also evaluated the biocompatibility of the AgNPs using hemoglobin (Hb) as a model protein. A comprehensive analysis of Hb and AgNP interactions was carried out by using various spectroscopic, imaging, and size determination studies. Spectroscopic results showed that the secondary structure of Hb was not altered after its interaction with AgNPs. Furthermore, the thermal stability was also well maintained at different concentrations of nanoparticles. This study demonstrated a low-cost, quick, and eco-friendly method for developing AgNPs using D. cordata, and the biocompatible nature of AgNPs was also established. D. cordata-mediated AgNPs have potential applications against bacteria and diabetes and may be utilized for targeted drug delivery.

Effects of Se nanoparticles supplementation on growth performance, hematological parameters and nutrient digestibility of Labeo rohita fingerling fed sunflower meal based diet.

The aim of the present study is to assess the effects of selenium nanoparticles on the growth, hematology and nutrients digestibility of Labeorohita fingerlings. Fingerlings were fed with seven isocaloric sunflower meal-based diet supplemented with different concentrations of nanoparticles naming T1 to T7 (0, 0.5, 1, 1.5, 2, 2.5, and 3 mg/kg), with 5% wet body weight while chromic oxide was used as an indigestible marker. After experimentation for 90 days T3 treated group (1mg/kg -1Se-nano level) showed the best result in hematological parameters (WBC's 7.97 ×103mm-3, RBC's 2.98 ×106 mm-3 and Platelet count 67), nutrient digestibility (crude protein: 74%, ether extract: 76%, gross energy: 70%) and growth performance (weight gain 13.24 g, weight gain% 198, feed conversion ratio 1.5, survival rate 100%) as compared to the other treatment groups. Specific growth rates were found significantly higher in T5 than in other groups. The present study indicated positive effect of 1 mg/kg Se-nanoparticles on growth advancement, hematological parameters, and nutrients digestibility of L. rohita fingerlings.

Density and viscosity of choline chloride/ethylene glycol deep eutectic solvent based nanofluid

In the present work, the effects of the SiO2, TiO2 and Al2O3 nanoparticles and temperature on the density and viscosity of choline chloride/ethylene glycol deep eutectic solvent based nanofluids were investigated. The choline chloride/ethylene glycol deep eutectic solvents with 1:2, 1:3 and 1:4 M ratio were used as the base fluid, and the nanofluids with different concentrations of nanoparticles were synthesized. All the nanofluids demonstrated Newtonian behavior. The density and viscosity of the nanofluids were measured from 303.15 K to 353.15 K and at atmospheric pressure. The experimental density and viscosity data were correlated using the model proposed by Sharifpur and Masoumi, respectively. In addition, the density and viscosity enhancement rate of different nanofluids were compared and discussed.

The effects of titanium dioxide (TiO2) nanoparticles on physiological, biochemical, and antioxidant properties of Vitex plant (Vitex agnus - Castus L)

Titanium dioxide nanoparticles (TiO2NPs) are widely used in agriculture in order to increase the yield and growth characteristics of plants. This study investigated the effects of TiO2NPs on photosynthetic pigments and several biochemical activities and antioxidant enzymes of the Vitex plant. Different concentrations of nanoparticles (0, 200, 400, 600 and 800 ppm) at five levels were sprayed on Vitex plants on the 30th day of the experiment. TiO2NPs at different concentrations had positive effects on root and shoot dry weight and a negative effect on leaf dry weight. The amount of chlorophyll increased with the concentration of TiO2NPs; however, the amount of chlorophyll b showed a decreasing trend while the total chlorophyll had a constant trend. The highest amount of soluble sugar was obtained in the treatment of 200 ppm nanoparticles. The application of TiO2NPs did not have any effect on the content of proline and soluble proteins of Vitex plant. The effects of foliar TiO2NPs, compared to the control, showed a significant increase in the activity of antioxidant enzymes. In general, TiO2NPs had a favorable effect on dry matter production and some antioxidant and biochemical properties of the Vitex plant.

Physical properties with high specific loss power of magnetite (Fe3O4) synthesized via thermal decomposition technique

Magnetic iron oxide nanoparticles have versatile applications in biomedical science that require control over shape and size distribution. Thermal decomposition is one of the best methods for controlling the size and shape of produced nanoparticles (NPs). The size distribution can be tuned (5–30 nm) by varying the reaction environment such as precursor concentration, amount of solvent used, temperature ramp, and reflux time. Iron oleate was used as a precursor solution and heated up to reflux temperature (310 °C) for 10 min within the oxygen-free environment by applying N2 gas flow. The XRD pattern confirmed the formation of NPs with a crystallite size of 17 ± 2.45 nm. Transmission electron microscope images showed moderately cubic shapes with a mean particle size of 28.67 ± 7.12 nm. Magnetic properties such as saturation magnetization, coercivity, and remanence were calculated at 23.48 emu/gm, 33 Oe, and 0.6 emu/gm, respectively, which indicated the ferromagnetic nature of the NPs. The Verwey transition was identified from the magnetization vs temperature (FC-ZFC) plot. The bondings of the oleic acid surfactant with the produced NPs were confirmed from Fourier transformation infrared spectroscopy (FTIR) data analysis. For the application of hyperthermia, the hydrophobic phase was transferred to the hydrophilic phase using cetyltrimethylammonium bromide, which was assured by the FTIR data analysis. The hyperthermia heating of NPs was measured for different concentrations of NPs (0.25, 0.5, 1, 2, and 4 mg/ml), from which specific loss power (SLP) was calculated. Among them, 0.25 mg/ml produced the most prominent SLP (2149 ± 309 w/g) that can be applied for targeted cancer treatment.

From synthesis to fabrication: Engineering thin translucent films with green persistent luminescent nanoparticles

Green-emitting ZnGa2O4:Mn2+ persistent luminescent nanoparticles were synthesized via a solvothermal method followed by a microwave-assisted sintering at 1150 °C. The obtained cubic-like particles averaged 62 ± 16 nm by Transmission Electron Microscopy (TEM) and presented afterglow for up to 2 h after a 5 min excitation in the UV. By Electron Paramagnetic Resonance (EPR), it was observed that the Mn2+ dopant replaces uniquely Zn2+ sites during synthesis. The obtained particles were dispersed with hydroxypropyl methylcellulose (HPMC) in water to create thin films by drop-casting. The films with different concentrations of nanoparticles (1 g/m2, 10 g/m2 and 100 g/m2) had average visible transmittances between 20% and 24%, and presented persistent luminescence after UV excitation, with longer duration by increasing nanoparticle concentration. By synchrotron X-ray Fluorescence (XRF) nanomapping of these films it is possible to see clusters of up to 6 μm of the nanoparticles in the film due to water pockets during film-casting. The X-ray Excited Optical Luminescence (XEOL) showed only Mn2+ emission and the XEOL-XRF mapping proved the integrity of the nanoparticles after film fabrication. By combining the solvothermal method, microwave-assisted sintering, and drop casting, this study establishes a promising pathway for the development of advanced flexible and translucent persistent luminescent composites.

Amelioration of cadmium stress by supplementation of melatonin and ZnO-nanoparticles through physiochemical adjustments in Brassica oleracea var. capitata

The Brassicaceae family, including the globally consumed Brassica oleracea var. capitata, faces multiple stressors like heavy metal toxicity, impacting their growth and quality. These stressors significantly impact plant growth, productivity, and overall quality. Particular nanoparticles and phytohormones play a pivotal role in regulating plant responses to such abiotic stressors. In the current study, the utilization of zinc oxide nanoparticles (ZnO-NPs) and melatonin (MT) was explored to enhance the resilience of Brassica oleracea var. capitata to cadmium (Cd) stress. The nanoparticles were synthesized in an environmentally friendly manner using Clinopodium vulgare L. leaf extract. Microscopic and spectroscopic techniques were employed to characterize the ZnO-NPs. Treatments were chosen as different concentrations of nanoparticles i.e., NP1 = 25 mg L−1 ZnO, NP2 = 50 mg L−1 ZnO, NP3 = 100 mg L−1 ZnO, MT = 200 µM, and NP0 (distilled water). The results revealed that ZnO-NPs showed a concentration-dependent effect on B. oleracea growth parameters and chlorophyll content, with the foliar application of MT further augmenting the impact. ZnO-NP treatments effectively reduced Cd concentrations while concurrently elevating zinc (Zn) levels in shoots and roots. The addition of exogenous MT further potentiated these effects. Notably, the treatments with 50 and 100 mg L−1 ZnO-NPs individually resulted in a growth increase of 38 % and 40 %, respectively, along with corresponding Zn content elevations of 20.1 % and 24 % compared to the control. The 100 mg L−1 ZnO-NPs treatment extended shoot length by 63.5 % and enhanced Zn content by 51 % compared to the control. ZnO-NPs and MT elevated total Cd absorption in shoots and roots, reducing post-harvest bioavailable Cd concentration in soil compared to the control. In conclusion, the synergy of ZnO-NPs and melatonin holds promise as a viable strategy to both counteract Cd toxicity and promote Zn bio-fortification in crops, presenting implications for healthier produce in contaminated soils.

Surface tension of Ag NPs-rGO based hybrid nanofluids

A novel type of hybrid nanoparticles/nanofluid is synthesized, characterized and prepared by suspending silver nanoparticles (Ag) and reduced graphene oxide sheets (rGO) in water (W) and water-ethylene glycol (W + EG) mixture. Experiments are carried out to determine the effects of the base fluid, concentration and temperature on the surface tension of solutions. Du-Noüy ring method is employed for the measurements. The surface tension of Ag NPs-rGO nanofluids is measured at temperatures ranging from 293.15 to 323.15 K and different concentrations of nanoparticles (0.050, 0075 and 0.10 wt%) respectively. The results show that the surface tension of the hybrid nanofluids is strongly influenced on presence/absence of sodium carboxymethyl cellulose (CMCNa) surfactant as well as the nanoparticles concentrations and temperatures. The surface tension is reduced by adding the surfactant to both base fluids and increasing temperature. An increase in concentration leads to increasing surface tension by nearly 7.5% and 2.4% with 0.10 wt% in concentration at 293.15 and 323.15 K, respectively for Ag NPs-rGO/water nanofluid. Similar for Ag NPs-rGO/water-ethylene glycol nanofluid, the increase in surface tension is 9.5% and 8.25% for the same conditions of concentration and temperature. These findings are promising for the use of Ag NPs-rGO nanofluids in boiling heat transfer.

Synergistic Effect of Water-Soluble Hydroxylated Multi-Wall Carbon Nanotubes and Graphene Nanoribbons Coupled with Tetra Butyl Ammonium Bromide on Kinetics of Carbon Dioxide Hydrate Formation

In this work, the thermodynamics and kinetics of hydrate formation in 9.01 wt% tetra butyl ammonium bromide (TBAB) mixed with water-soluble hydroxylated multi-wall carbon nanotube (MWCNTol) systems were characterized by measuring hydrate formation conditions, induction time, and final gas consumption. The results showed that MWCNTols had little effect on the phase equilibrium of CO2 hydrate formation. Nanoparticles (graphene nanoribbons (GNs) and MWCNTols) could significantly shorten the induction time. When the concentration was ≤0.06 wt%, MWCNTols had a better effect on the induction time than the GN system, and the maximum reduction in induction time reached 44.22%. The large surface area of MWCNTols could provide sites for heterogeneous nucleation, thus shortening the induction time of hydrate formation. Furthermore, adding different concentrations of nanoparticles to the 9.01 wt% TBAB solution effectively increased the final gas consumption, and the maximum increase was 10.44% of the 9.01 wt% TBAB + 0.08 wt% GN system. Meanwhile, the suitable initial pressure and experimental temperature could also promote the hydrate formation and increase the motivation in hydrate formation. The 9.01 wt% TBAB + 0.02 wt% MWCNTol system had the best effect at 3.5 MPa and 277.15 K. The induction time was reduced by 66.67% and the final gas consumption was increased by 284.11% compared to those of the same system but at a different initial pressure and experimental temperature. This work helps to promote the industrial application of hydrate technology in CO2 capture and storage.

Surfactants Effects on Enhancing Electrical Performance of Nanoparticle-Based Mineral Transformer Oil

Introducing nanoparticles to enhance the performance of mineral transformer oil has been considered in many studies recently. Typically, researchers focused on the use of widespread types of nanoparticles like aluminum oxide, silicon dioxide, titanium dioxide, etc. However, there is no consensus on which type, or concentration is suitable for this application. In this paper, the authors studied different types of nanoparticles to investigate their effects on the electrical performance of mineral transformer oil with and without the use of surfactants. Design-of-experiments (DOE) approach was adopted to systematically produce oil-based nanoparticles, referred as nanofluids, under different concentrations of nanoparticles and surfactants. With three concentration levels of three nanoparticles, namely zinc iron oxide (ZnFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ), titanium carbide (TiC), and molybdenum dioxide (MoO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ), the nanofluids were produced with three types of surfactants, which were oleic acid (OA), cetyl trimethyl ammonium bromide (CTAB), and polyvinyl alcohol (PA) under three different concentrations. Fifty successive AC breakdown voltage tests were carried out for each sample using mushroom-mushroom cell according to IEC 60156. The results showed the dominance of TiC for two samples with and without surfactants. Additionally, the DOE results showed the importance of concentration of nanoparticles and their types to enhance mineral oil’s performance.

Preparation of Biocompatible Manganese Selenium-Based Nanoparticles with Antioxidant and Catalytic Functions.

The specificity of the tumor microenvironment (TME) severely limits the effectiveness of tumor treatment. In this study, we prepared a composite nanoparticle of manganese dioxide and selenite by a one-step redox method, and their stability under physiological conditions was improved with a bovine serum protein modification to obtain MnO2/Se-BSA nanoparticles (SMB NPs). In the SMB NPs, manganese dioxide and selenite endowed the SMB NPs with acid-responsive and catalytic, and antioxidant properties, respectively. The weak acid response, catalytic activity, and antioxidant properties of composite nanoparticles were verified experimentally. Moreover, in an in vitro hemolysis assay, different concentrations of nanoparticles were incubated with mouse erythrocytes, and the hemolysis ratio was less than 5%. In the cell safety assay, the cell survival ratio was as high as 95.97% after the co-culture with L929 cells at different concentrations for 24 h. In addition, the good biosafety of composite nanoparticles was verified at the animal level. Thus, this study helps to design high-performance and comprehensive therapeutic reagents that are responsive to the hypoxia, weak acidity, hydrogen peroxide overexpression nature of TME and overcome the limitations of TME.

Performance enhancement and emission reduction of CRDI diesel engine fueled using Manilkara Zapota biodiesel blend with TiO2 nanoadditive

The serious issues faced in recent years, globally, are the environmental pollution concern and fuel resource depletion. In this work, the effect of TiO2 nanoadditive in the optimized biodiesel blend of 15% fueled in a stationary single cylinder, 4-stroke naturally aspired CRDI diesel engine to assess the engine performance as well as the combustion and emission characteristics. The results of the prepared fuel samples are compared against using neat diesel fuel. Initially, a Soxhlet apparatus is used to extract the oil from the grounded Manilkara Zapota seed. Moreover, the oil derived from the Soxhlet method would be more viscous and a standard transesterification process is employed to reduce the viscosity. The M. Zapota biodiesel are characterized, and the analysis such as GC–MS (Gas chromatography – Mass spectrometry), FT-IR (Fourier transform Infra-red spectrum), NMR (Nuclear magnetic resonance) are performed. Similarly, the TiO2 nanoparticles are characterized based on surface morphology (FESEM, EDX, and XRD analysis). Three different concentrations of nanoparticles, namely 25, 50, and 75 ppm, are added to a 15% biodiesel blend in diesel fuel. The properties of the prepared fuel samples such as kinematic viscosity, calorific value, cloud point, flash point, cetane index are measured and compared with diesel fuel. The in-cylinder pressure developed during the combustion are lowered with increased TiO2 concentration and moreover, the neat heat release rate by the biodiesel blend using 50 ppm TiO2 nanoadditive is lowered to 29.9 J/oCA whereas, further addition increased the net heat release rate to 31 J/oCA which might be due to higher flame temperature during combustion. The HC emissions are lowered for S15 biodiesel blend with TiO2 NP's in the concentration of 50 ppm and moreover, the NOx formation from the engine for biodiesel blend with 50 and 75 ppm TiO2 nanoadditives are almost similar and significantly lowered. The formation of NOx using neat diesel, biodiesel, and biodiesel with 25, 50 and 75 ppm TiO2 nanoadditives in the engine are found as 600, 609, 556, 509 and 505 ppm, respectively. From the experimental analysis, it is found that the formation of NOx and CO emission reduces during the part load application of diesel engine with slight increase in CO and CO2 emissions and a reduction in cylinder peak pressure and net heat release. Manilkara Zapota seed oil biodiesel blend with diesel at 15% volume proportion along with 50 ppm TiO2 nanoadditive was proven to be a potential replacement for CRDI diesel engines with reduced HC and NOx emission with a slight compromise over the performance of engine.

A Critical Overview of the Impact of Nanoparticles in Ester Fluid for Power Transformers

This paper examines the impact of various nanoparticles on ester fluids with a special focus on their usage towards power transformers. The precautionary measures to be considered on the nanofluids such as preparation methodologies with an appropriate surfactant and its stability is well elucidated. The electrical double layer (EDL) formation around the nanoparticles on its diffusion in the insulating fluid is explained by its different layers away from the particle surface. The partial discharge of ester nanofluids with different detection methods is elaborated on its comparison with conventional IEC 60270 measurements. The field configurations on ester-nanofluids govern the breakdown mechanism with variations in the streamer patterns. The equation of relaxation time towards breakdown is valid only when it is lower than the initiation time for streamers. The flow charges induced at the solid/liquid interface inside transformers depends on the structure of the nanofluid and the condition of pressboard/paper insulation. The impact of different concentrations of nanoparticles on ester nanofluids observes a change in its flow behaviour affecting the streaming current. The permittivity of nanofluid depends on the polarization of nanoparticles where the Clausius-Mossotti equation governing this mechanism is explained towards ester-nanofluids. The viscosity of nanofluids observed no significant variation whereas the other physio-chemical properties such as flash point, interfacial tension, and oxidation stability improved depending on the type of nanoparticle. The addition of metal-oxide nanoparticles on ester fluids increases thermal conductivity with different models proposed based on the structure and shape of a nanoparticle. The impact of ageing on nanofluids observes an instability over a longer ageing duration with specific nanoparticles which should be better understood before implementing them in real-time power transformers.