Different Concentrations Of Nanoparticles Research Articles

Molecular simulation of liquid-liquid extraction of acetic acid and acetone from water in the presence of nanoparticles based on prediction of solubility parameters

In this work, molecular dynamics simulation (MD) was used for studying the liquid-liquid extraction of acetic acid and acetone from water in the presence of nanoparticles. In the next step, the solubility parameter of acetic acid and acetone were predicted at 1 atm and different temperatures along with the solubility parameter of solvents and water at 25 °C and 1 atm. Three pure systems and three systems with different concentration of nanoparticles were investigated to show the effect of cell size or number of molecules on the solubility parameter. With the addition of SiO2 nanoparticles to the solvents, at low concentrations of nanoparticles (0.01–0.1 vol%), the solubility parameter is increased due to the Brownian motion. With the further increase concentration of the nanoparticles, the solubility parameter decreases due to the accumulation of nanoparticles. The difference between the solubility parameter of benzene and acetone was 0.414 (J/cm3)0.5 and 3.13 (J/cm3)0.5, with and without the presence of SiO2 nanoparticles, respectively. Finally, toluene was found to be the best solvent for acetone and acetic acid at silica nanoparticles concentration of 0.062 vol%.

Influence the foliar application of smoke-water and Fe, Zn, Ti nanoparticles on some qualitative and quantitative characteristics of sage (Salvia officinalis L.)

ABSTRACT This research has investigated the effect of different concentrations of nanoparticles (zinc, iron, titanium) and smoke-water on some growth and physiological characteristics of the medicinal plant sage. A factorial experiment was conducted in the form of a randomised complete block design with three replications in the research greenhouse of the Campus of Agriculture and Natural Resources, Razi University, Iran, over two consecutive years, 2021 and 2022. The first factor included foliar spraying of nanoparticles of Fe, Zn, Ti with two levels: 0 and 50 mg l−1. The second factor was foliar spraying using smoke-water with two levels of 0.5 and 1 mg l−1. Treatments were applied in three stages after graft establishment. Results indicated that the highest stem dry weight (68.477 g) occurred with 0.5 mg l−1 smoke-water without nanoparticles. At 0 mg l−1 smoke-water, titanium (64.493 g) and iron (65.193 g) nanoparticles yielded the highest stem weights. Application of 0.5 mg l−1 of smoked water improved the dry weight of leaves and stems. Foliar spraying of 50 mg l−1 of zinc and titanium nanoparticles also increased growth characteristics and chlorophyll content of sage leaves. In both cuttings, different concentrations affected some growth characteristics and photosynthetic pigments of sage plants.

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

أجري البحث لغرض دراسة تأثير تراكيز مختلفة من الجسيمات النانوية (الكيتوزان وثاني أكسيد التيتانيوم) و Fusarium oxysporum كمحفزات لزيادة إنتاج المركبات الفعالة من كالس نبات المسواك. اظهرت نتائج المحتوى الكلي مركبات الفلافونويد والقلويدات التي ازاد انتاجها عند اضافة الكيتوسان بتركيز 5 ملغم / لتر، وثاني أكسيد التيتانيوم بتركيز 1 ملغم / لتر، و Fusarium oxysporum بتركيز 5 ملغم / لتر حيث اعطت 93.10 ملغم / 100 ملغم، 128.7 ملغم / 100 ملغم، و 107.61 ملغم / 100 ملغم على التوالي للفلافينودات بينما ساعدت المحفزات على انتاج القلويدات بمعدل 2.39 %، 3.91%، و2.20% على التوالي. وأوضحت النتائج التفوق في وجود مركبات الفلافونويد في العينات مقارنة مع القلويدات. بين تحليل HPLC( تحليل كروماتوغرافي سائل عالي الأداء) اختلافات كبيرة في زيادة إنتاج الفلافونويد (Rutin, Kaempferol, Quercetin, Catechin, Luteolin, and Apigenin) أدت إضافة الكيتوسان عند التركيز 5 ملغم / لتر إلى زيادة إنتاج Rutin ، بمقدار 39.89 ملغم/لتر. أما الكالس المستحث المعالج بثاني أكسيد التيتانيوم بتركيز 1 ملغم/لتر فقد أدى إلى زيادة Rutin بمعدل 35.89 ملغم/لتر. بينما ارتفع إنتاج Rutin إلى 30.12 ملغم/لتر عند معاملته بـ Fusarium oxysporum بتركيز 5 ملغم/لتر.

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

The green synthesis route is becoming an emerging field of study in nanotechnology due to its biodegradability, eco-friendly nature, and non-hazardous nature. Among a variety of industrial metal nanoparticles (NPs), copper oxide nanoparticles (CuONPs) are the most attractive topic for researchers because of their effective surface area to volume ratio, chemical properties, and antimicrobial activity. The current study consists of the synthesis of Copper oxide nanoparticles (CuONPs) using Cassia fistula extract as a reducing and capping agent and studies its antibacterial activity. The formation of Cassia Fistula mediated CuONPs was identified by color change and was confirmed by FTIR and UV-visible spectrophotometry, revealing an absorbance peak at 235 nm. A shift of 45 nm was observed when the NPs were coated with PEG. Astonishingly, CuONPs showed a virtuous result on 485 ug/ml, showing only 3% of hemolysis; meanwhile, many different concentrations of NPs were used to check whether it would exceed the standard value. However, none of the diluted concentrations were above the standard value, making them biocompatible. The MIC test was performed, showing 250 ml and 350 ml of diluted CuONPs were prominent concentrations for the elimination of bacteria. ROS quantification and identification showed that the ROS produced followed the Type II mechanism in which the singlet oxygen transfers energy to triplet oxygen. We settled that CuONPs possess the ability to delimit the bacteria, specifically Salmonella typhi.

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.

Investigating the Alkaline Potential of Mineral Trioxide Aggregate Repair Using Selenium Nanoparticles

This study aimed to determine the effect of adding selenium nanoparticles (SeNPs) to mineral trioxide aggregate (MTA HP) concerning alkalinizing potential. Additionally, it examined the set material after SeNPs incorporation using Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray analysis (FE-SEM/EDX) for characterizing the elemental composition and morphological alterations resulting from the integration of SeNPs. Cement samples, both before and after SeNPs incorporation, were examined using FE-SEM/EDX. The pH level was also measured with a pH-meter previously calibrated with solutions of known pH, to evaluate the alkalinizing activity of the integrated substance at different concentrations of nanoparticles: Group 1 (control): 0% w/w SeNPs, Group 2: 0.5% w/w SeNPs, Group 3: 1% w/w SeNPs, Group 4: 1.5% w/w SeNPs and Group 5: 2% w/w SeNPs after 1, 7, 14, and 30 days in distal water. The data were analyzed by one-way ANOVA and Tukey tests (P≤0.05). According to FE-SEM/EDX, the morphological characteristics indicate that SeNPs were successfully dispersed and integrated into the MTA repair matrix. EDX examination validates the presence of Selenium, confirming successful integration. The findings confirmed that the MTAHP showed a high pH level with a discernible reduction in the alkalinizing activity with each incorporated concentration of (SeNPs) that significantly differed from the control group across various periods at (P≤ 0.05). Consequently, the findings indicate that the addition of SeNPs to MTA HP has a notable impact on the pH of the storage solution, leading to a significant decrease in pH values for all concentrations and periods when compared to the control group. The alkalinizing action of MTA HP is highly affected by the incorporated SeNPs, making it more suitable for application in pulpal tissue. This study contributes to our understanding of the morphological alterations and elemental composition of SeNP-incorporated MTA HP, enhancing its potential applications in dental and tissue regeneration.

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.