Optimum Nanoparticle Concentration Research Articles

Optimization of Nanofluid Concentration for Energy Intensification in Corrugated Plate Type Heat Exchanger

The overall heat transfer coefficient of the heat exchanger will improve with an increase in the flow rate and concentration of nanofluid. But beyond an optimum nanoparticle concentration, the overall effectiveness seems to decrease due to an increase in pressure drop that consequently leads to an increase in pumping power. The novelty of the present work is to find the optimum concentration of CuO-Water nanofluid that exhibits the optimum heat transfer rate and global minimum pumping power, using both experimental and numerical study. The cold nanofluid and hot water entered the counter currently at 303.15 and 333.15 K respectively in the corrugated plate heat exchanger. It was observed from the experimental and numerical results that the values of overall heat transfer coefficient and pressure drop were increased monotonically (454–710 W/(m2-K) and 6–133 Pa respectively), with the increment in the concentration and flow rates of the nanofluid. Because of this trend, it was challenging to figure out the optimum nanofluid concentration using these parameters. Later, a procedure was presented to obtain an optimum concentration of nanofluid, to reduce the hot stream temperature by 288.15 K. The hydraulic power exhibited a global minimum at an optimum concentration of 0.5 vol% of nanofluid.

Experimental and data-driven analysis for predicting nanofluid performance in improving foam stability and reducing mobility at critical micelle concentration

Application of surfactant-based foam flooding is an effective approach to reduce mobility and control early breakthrough. Despite the proper performance of surfactant-based foams in decreasing the channeling of the flooded gas and water, high pressure, high temperature, and high salinity of the reservoirs put some limitations on the foam flooding efficiency. Nanoparticles are used to improve the quality of the foams, enhance stability, and transcend the limitations. Although there are many benefits of using nanoparticles in foam flooding, their performance at surfactant critical micelle concentration (CMC) is not fully investigated and the optimum nanoparticle concentration is not specified. In this study, an experimental investigation using nanosilica with surfactants at CMC to improve the stability (half-life) and mobility reduction factor (MRF) has been conducted. Furthermore, data from the literature were collected and analyzed to evaluate the change in MRF and stability for a nanofluid-based foam at CMC. Both experimental results and literature data showed that application of nanofluid-based foam is a successful approach to develop a more stable foam with lower mobility. Nanoparticle (NP) concentration is the dominant parameter at different salinities and temperatures that affects foam flow through porous media. The range of 0.2–0.4 wt% is the optimum nanoparticle concentration to develop a strong foam with acceptable performance in controlling mobility.

Rheology‐cell structure correlation for foam processing of polypropylene‐titanium dioxide and polypropylene‐graphene nanocomposites

AbstractThis work focuses on understanding the effects of nanoparticle fillers (titanium dioxide (TiO2) and graphene) on foam processing of polypropylene(PP) and makes an attempt to establish a rheology‐cell size correlation for PP‐TiO2 and PP‐graphene nanocomposite foams. The establishment of such a correlation can help develop a precise model to predict optimum nanoparticle concentration in a polymer matrix to produce stable microcellular foams. The effects of adding TiO2 and graphene nanoparticles on nanocomposite properties are studied through their thermal, mechanical, and rheological analysis. The nanocomposite/PP foams are prepared at various conditions, and their morphology and density are studied to obtain an understanding of the cell structure as a function of added nanoparticles. The optimized size/structure has also been correlated in terms of rheological and mechanical properties of the prepared nanocomposites to study the effects of variation in rheological properties on the resultant cell structure of prepared foams. Through the current work it was found that particle type/size plays the dominant factor in determining the cell size of resultant foam, although when comparing foams with varying filler concentration, it was established that a decrease in viscosity and storage modulus would create more cell stability by decreasing the applied stress and would lead to smaller cells.Highlights Rheological property variation can directly affect the polymer foamability Foaming of polymers can be closely simulated using the Maxwell model for polymers Reduction in viscosity leads to smaller and stable cells during foaming Stress relaxation rate determines the cell stabilization during expansion Agglomerate size plays a crucial role in determining cell size

Screen-printed Sn-doped TiO2 nanoparticles for photocatalytic dye removal from wastewater: A technological perspective

TiO2 is widely used as a photocatalyst with a wide band gap, which limited its application. Ion doping and formulating a high-quality screen-printing paste enhance its features. However, the printability of objects for advanced application seems essential nowadays. In this research, the Sn-doped TiO2 nanoparticles were prepared through a sol-gel method followed by calcination at various temperatures of 450 °C, 550 °C, 650 °C, 750 °C, and 850 °C. Screen-printing pastes were prepared with 18 wt% of the synthesized Sn-doped TiO2 nanoparticles to evaluate photocatalytic activity. Finally, the prepared paste with optimum nanoparticle concentration was screen printed onto the microscope glass slides at various printing times (1, 3, and 5 runs) and annealed at 500 °C temperature to investigate the thickness of printed Sn-doped TiO2 nanoparticles effect. The photocatalytic activity and crystal structure of nano Sn-doped-TiO2 were characterized using photoluminescence (PL) spectroscopy and X-ray diffraction (XRD). Transmission electron microscopy (TEM) and scanning electron microscope (SEM) analyses were conducted to investigate the size and morphology of the prepared nanoparticles, respectively. The highest photocatalytic activity for the degradation of methylene blue was obtained at the calcination temperature of 450 °C.

Tribological characterisation of graphene hybrid nanolubricants in biofuel engines

The rapid development of nanotechnology allows further enhancement of the tribological performance of lubricants by utilizing nano-additives. This study used a four-ball tribometer to examine the tribological properties of three different oils, namely 15 W-40 mineral oil, 5 W-30 completely synthetic polyalphaolefin with ester oil and pongamia oil with additional graphene nanoplatelets. The experiment model was constructed using a mathematical technique known as Response Surface Methodology (RSM), with the experimental design developed by using Optimal Custom Design. The extent of the influence to which various operating parameters, including load, speed and concentration of nanoparticles, were assessed by analysis of variance (ANOVA) and regression analysis. The simulation results are used for optimization purposes to determine the optimum concentration of nanoparticles that provides excellent tribological properties. The surface morphology was analysed using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy to explore the mechanisms that improve the tribological performance. The optimum concentration of graphene nanoplatelets (GNP) was determined to be 0.126 wt%, 0.15 wt%, and 0.096 wt% for mineral oil, synthetic polyalphaolefin with ester oil and pongamia oil respectively. The optimization of graphene nanoplatelets (GNP) concentration on mineral oil (MO), synthetic oil (SO) and Pongamia oil (PO) exhibits 5.78, 15.63 and 6.82% friction reduction respectively and 17.68, 29.46 and 97.32% wear reduction respectively compared to base oils. The dispersion stability results show that GNP is more stable in MO and SO than PO in the absence of surfactant. Finally, the improvement on worn surface was observed with optimization of concentration due to the significant polishing effect of GNP.

Enhancement in vanadium redox flow battery performance using reduced graphene oxide nanofluid electrolyte

Low energy storage performance of aqueous flow batteries is the main limitation in commercialization and worldwide implementation. The effect of nanofluids on the electrochemical behaviour of electrolytes to alleviate this problem has been rarely studied in contrast with the extensive heat-transfer-related literature on nanofluids from the field of thermal science. Therefore, this study aims to experimentally investigate the long-term effect of using reduced graphene oxide (rGO) nanofluidic electrolyte on vanadium redox flow battery performance, placing it amongst the very few studies on the effectiveness of nanofluids in flow batteries. Scanning Electron Microscopy (SEM), EDS elemental mapping, X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) characterizations reveal changes in morphology, structural and elemental properties of the carbon felt electrodes due to the presence of suspended nano catalysts in the electrolyte. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) exhibited significant improvements of 36 % and 26 % in oxidation/reduction peaks, ~ 95 % of reduction in charge transfer resistance, and enhanced redox reactions reversibility of the optimum concentration of nanofluidic electrolyte (0.1 wt%). Moreover, active surface area of the electrodes were determined to be increased by ~130 % and ~ 135 % for positive and negative 1.0 wt% nanofluid-affected electrode samples compared to pure electrolyte-affected electrode. In addition, considering the optimum nanoparticle concentration of 0.1 wt%, charge, and discharge capacities of the flow battery outperformed where pure electrolyte was applied in different current densities. These enhancements show considerable increase in energy storage of the VRFB. Furthermore, energy efficiency and voltage efficiency of the flow cell were observed to be increased respectively by 15 % to 24 % and 8 % to ~21 % for the current densities from 25 to 150 mAcm−2 when the optimum concentration of nanoparticles was applied. This study gives new insight into the rarely studied applicability of nanofluids in vanadium flow batteries.

Recovered Reverse-Osmosis Water and MgO Nanoparticles for Improved Performance of Solar PV/T Systems

Domestic RO systems are commonly installed in households for water purification and treatment, typically for drinking water purposes. While RO systems effectively remove impurities, such as dissolved salts, minerals, and contaminants from tap water, they produce a concentrated waste stream known as RO reject. This reject water contains the contaminants that were removed during the RO filtration process. This RO reject can be effectively utilized in other domestic, agricultural, and industrial applications. In this study, the performance of a photovoltaic/thermal (PV/T) system was experimentally examined by employing RO reject and MgO/water-based nano-fluid. Two 165 W polycrystalline solar PV modules were used to compare the performance of a PV/T and a PV module. The performance of the solar PV module was assessed in terms of cell temperature and electrical efficiency using a water- and MgO/water-based PV/T system. Furthermore, the thermal and overall efficiency of the PV/T module was also compared using different base fluids. The effect of the working fluid flow rate (3 LPM, 6 LPM, 9 LPM, and 12 LPM) and variations in the concentrations (0.10 wt.%, 0.15 wt.%, and 0.20 wt.%) of MgO nanoparticles were examined to evaluate the improvement in the performance of the PV/T system. The results indicate that the PV/T system’s cell temperature was significantly reduced, and its electrical, thermal, and overall efficiency increased with an increased flow rate. The optimum concentration of nanoparticles and flow rate were determined to be 0.15 wt.% and 12 LPM, respectively. The findings suggest that MgO/water-based nano-fluids have the potential to enhance the performance of PV/T systems, and this study provides valuable insights for their practical implementation.

A comprehensive study to find the optimal fraction of nanoparticle coated at the interface of solar desalination absorbers: 5E and GHGs analysis in different seasons

In recent years utilizing nanoparticles in black paint (nano-paint) of solar desalination absorbers has become a topic growing interest. However, in most of studies, only the effect of using different types of nanoparticles brought into the spotlight, while in those limited studies that discussed on optimum concentration of nanoparticles, the results were controversial and not conclusive. Herein, an experimental study to find the optimum concentration of nanoparticles (silver, 1–5%) in solar absorbers in summer, spring and autumn with/without reflectors was conducted. To find the optimum concentration, performance of the systems from different viewpoints including energetic, exergetic, economic, productivity, exergoeconomic, energy-matrices, and environmental (amount of CO2/SO2/NO emission/reduction) analysis for each season and thorough its lifetime was examined thoroughly. Ascribe the highly variable of parameters; two Matlab codes have been developed to precisely calculate the economic and exergoeconomic parameters for different scenarios. The results showed that increasing the nanoparticle concentration to 5% from an economic viewpoint was reasonable just in summer, while for autumn and spring, 2.5% was optimum. The same was valid for productivity and exergy analysis. Importantly, the embodied energy of nanoparticles for the first time considered in calculation to obtain more accurate results in terms of environmental analysis and energy-matrices. Finally, it was concluded that even though using 5% nanoparticle in limited cases led to better results, the 2.5% concentration with reflector was optimum for all seasons and through the lifetime. This work would be a cornerstone for future researches in the context of using nano-paint in solar absorbers.

Direct absorption solar collector: Use of nanofluids and biodegradable colloids

In this paper, an experimental and numerical analysis was performed on both carbon black nanofluids and a biodegradable fluid in a novel pump-free direct absorption solar collector (DASC). In the experiments, the nanofluid consisted of carbon black nanoparticles in water with concentrations ranging from 0.005 to 0.020 wt%, while the biodegradable fluid was coffee colloid. The overall findings indicated a concurrence: the nanofluids exhibited the best thermal performance when compared to pure water. The optimum nanoparticle concentration of 0.010 wt% carbon black yielded a 102% thermal enhancement compared to the base fluid. Furthermore, a numerical analysis using computational fluid dynamics (CFD) software was performed to study the experimental rig. According to these simulations, the optimal nanofluid concentration showed a 76.6 - 90.9% increase compared to the base fluid. The biodegradable fluids did not show a significant enhancement in the experiments, which differs from what has been reported in the scientific literature. Nevertheless, from the computer simulations, the biodegradable fluids also slightly outperformed the case when the pure water was used.

Purification of Biodiesel via Nanofluid using Liquid-Liquid Extraction in a Membrane Contactor

Recently, attention has been paid to nanofluids due to their contribution to enhancing heat and mass transfer in different industrial applications. Consequently, a nanofluid composed of SiO2 nanoparticles (NPs) and distilled water as base fluid was adopted as a solvent to promote the removal of impurities, methanol, and glycerol, from crude biodiesel using liquid-liquid extraction in the membrane contactor. The presence of NPs significantly enhanced the methanol and glycerol removal efficiency. The optimum concentration of NPs in nanofluid was 0.01 wt%. It was found that adding 0.01 wt% of NPs to the distilled water increased the methanol removal efficiency from 76.4% to 93.1% upon using crude biodiesel with methanol and glycerol content of 2000 ppm and 1 wt%, respectively, at a constant flow rate of solvent and biodiesel of 200 mL min⎼1. Meanwhile, the glycerol removal efficiency increased from 76.2% to 94.5%. The results revealed that the solvent flow rate was the controlling mass transfer step.

Thermal and Tribological Properties Enhancement of PVE Lubricant Modified with SiO2 and TiO2 Nanoparticles Additive

The addition of nanoparticles may have a positive or negative impact on the thermal and tribological properties of base lubricant. The objective of this paper is to investigate the effect of nanoparticle dispersion in lubricant base in relation to its application in refrigeration system compressors. An investigation of tribological and thermal properties of nanolubricants for rolling piston rotary systems was carried out through four-ball tribology tests and thermal conductivity measurements. Nanolubricants dispersed with SiO2 and TiO2 nanoparticles were tested at various concentrations and temperatures. The changes in thermal conductivity and coefficient of friction (COF) were analyzed while wear weight loss was also calculated from wear scar size. A regression model of thermal conductivity enhancement was proposed for both types of nanoparticles. Zeta potential results show that nanolubricants have excellent stability. The thermal conductivity increases by the increment of nanoparticle concentration but decreases by temperature. The R-square for the regression model is more than 0.9952 with an average deviation not more than 0.29%. The COF for SiO2/PVE nanolubricant at 0.003 vol.% reduced 15% from the baseline. The COF for nanolubricants exceeds the result for base lubricants when the concentration is more than the threshold value. The optimum concentration of SiO2 and TiO2 nanoparticles improved the thermal and tribological properties of PVE lubricant and may offer an advantage when applied to refrigeration systems.

Antibacterial and Antioxidant Activities of Edible Film Incorporated with Silver Nanoparticles Synthesized using Rhizophora mucronata Extract

Edible film is an alternative packaging material to replace plastic. Protecting the product from oxidation processes and microbiological activities is one of its functions. One of the biopolymers used for the base of the edible film is fish gelatine from Pangasius sp. skin. Silver nanoparticles from Rhizophora mucronata were added to increase the edible film’s antioxidant and antibacterial ability. This study aims to determine the effect of silver nanoparticles from Rhizophora mucronata on the edible film‘s antioxidant and antibacterial activity. The method used in the research was the experimental method with five treatments of silver nanoparticles from Rhizophora mucronata concentration (0%, 2%, 4%, 6%, 8%). A statistical approach used was Simplex Lattice Design. Antioxidants and antibacterial (Escherichia coli, Salmonella sp. Staphylococcus aureus) of edible films were analysed. The results showed that the different concentrations of silver nanoparticles from Rhizophora mucronata significantly affected edible films’ antioxidant and antibacterial activity. The antioxidant activities of enriched edible film ranged from 41,085% to 66,815%. Weak antibacterial activities of the edible film were recorded for three bacteria species: Salmonella sp. 0.07mm-0.26mm; Escherichia coli 0.215mm-0.575mm; Staphylococcus aureus 0.33mm-0.44mm. The optimum concentration of silver nanoparticles from Rhizophora mucronata was 5.96%.

Experimental study on hydrodynamic behaviour of nanofluid particle moving through an immiscible quiescent liquid

In the present study, experiments were conducted to study the motion of nanofluid drops moving through an immiscible quiescent liquid for the liquid-liquid extraction process. An extensive set of data in terms of terminal velocity were generated using three different systems (Chlorobenzene, Tetrachloroethylene, and Nitrobenzene) covering a wide range of properties. To elucidate the effect of the addition of nanoparticles on hydrodynamic parameters, four nanoparticles (SiO2, Al2O3, ZnO, and MWCNTs) have been taken. It is observed that with the addition of nanoparticles into the system, the terminal velocity increases up to an optimum concentration of nanoparticles, beyond which it started to decrease. On the addition of nanoparticles to the base fluid, the internal circulation within the drop increases due to Brownian motion and micro convection which in turn leads to an increase in terminal velocity and a decrease in the drag coefficient. Based on the observed data, the existing model of Grace et al. [1] for contaminated drops and bubbles, is extended to predict the terminal velocity and drag coefficient for nanofluids in terms of J and H factors. The J factor has been modified, Jmod=J(1+a(φτbdτcd)b), to account for the presence of nanoparticles in terms of nanoparticle volume fraction (ɸ), the time scale for Brownian motion diffusion (τbd), and the time scale for nano convection diffusion (τcd). The proposed correlation predicts the experimental data well to within a reasonable accuracy of ±8% with MRQE and %ARE of 0.038 and 2.99%, respectively for terminal velocity and 0.081 and 6.28%, respectively for the drag coefficient.

Improvement of gas hydrate-based CO2 capture from CH4/CO2 mixture using silica and modified silica nanoparticles in the presence of potassium hydroxide

Separation of CO2 gas from CO2/CH4 mixture (74 mol% of CH4 and 26 mol% of CO2) was investigated, experimentally using the gas hydrate formation method in a constant-volume vessel. Silica and (3-aminopropyl) teriethoxysilane (APTES) surface-modified silica nanoparticles in the presence of potassium hydroxide were employed as additives. The impacts of various parameters such as initial pressure, gas–liquid ratio, and nanoparticle concentration were studied on gas consumption, separation factor, and recovery factor of CO2 gas in the separation process. Experiments were performed at 277.15 K and two initial pressures of 3.0 and 4.0 MPa. The presence of silica had a positive effect on gas consumption, separation, and recovery factors. The optimum results are obtained for the nanofluids including silica and potassium hydroxide, which at best case improved the gas consumption, separation factor, and recovery factor by 36 %, 29 % and 38 % compared to the pure water, respectively. The optimum nanoparticle concentration was obtained to be 0.1 wt% Besides, as the gas–liquid ratio increased, the gas consumption value raised. However, the relative amount of gas consumption and the recovery factor decreased. While the gas consumption was a direct function of the initial pressure, the separation and recovery factors were inverse functions of that.

Laser ablated silver nanoparticles doped blue light-emitting polymer optical fiber with enhanced photostability

Here, we demonstrate the fabrication of a stable polymer optical fibre doped with 1,4-bis (2-methylstyryl) benzene (Bis-MSB) that contains silver nanoparticles. Spherical silver nanoparticles of approximate size 15 nm were fabricated using nanosecond laser ablation. A Q-switched Nd: YAG laser operating at 355 nm was used to pump the polymer optical fiber in order to analyse its emission characteristics. The pump pulse energy (PPE) dependent emission spectra from the fiber were analyzed. The observed fluorescence emission was turned to amplified spontaneous emission (ASE) at a PPE of 2.5 mJ. The study demonstrates that the fibre offers superior photostability at an optimum concentration of Ag nanoparticles. The proposed fiber may find potential applications in the development of stable directional optical sources in the blue region.

Performance of Equilibrium Zeolite in Water-Based Mud at Elevated Temperature Conditions

This study looks at the performance of nano equilibrium zeolite treated drilling fluids at high temperatures conditions, and their potential as alternatives for oil-based muds (OBM). Mud samples for this study were prepared and aged with the equilibrium zeolite nanoparticles concentrations of 0.0 g, 0.5 g, 1.0 g and 1.5 g. Tests were performed to determine the rheological, filtration control properties, the pH and consequently the thermal stability of the study mud samples over a temperature range of 120 °F to 360 °F. One sample without the equilibrium zeolite served as a control for the study. From the results obtained, all the nano samples had their rheological properties not exhibiting much significant variation with temperature, thus they were more thermally stable, with the optimum nanoparticle concentration being 1.5 g. It was also hypothesized that the nano equilibrium zeolite behaved as thinners, since they were able to reduce the shear stresses, yield points, plastic viscosities and gel strengths of the mud samples as temperature was varied incrementally. It was therefore concluded that the optimum concentration of aged equilibrium zeolite has the potential to act as a thermal stability additive for Water Based Mud systems (WBMs).

Monitoring of microscopic behavior of nano-enhanced colloidal gas aphron in fractured and un-fractured non-uniform porous medium

The present article aimed to examine the pore-scale examination of a fluid capability to block pores and fractures deduced by return permeability and the blocking ability of a novel lightweight Colloidal Gas Aphron Nano-Fluid (CGANF) in heterogeneous fractured/un-fractured porous medium. Silica (S) and fumed silica (FS) nanoparticles, Sodium Dodecyl Sulfate (SDS) anionic surfactant, and Xanthan Gum (XG) bio-polymer were employed for following up CGANF bubbles' movements in incongruous micro-models’ inclusive crack. The transparent nature of the glass micro-model provides an intuition into the lenticular behavior of CGANF bubbles in the heterogeneous porous media. Differential pressure analysis through porous media during experiments demonstrated that opposition to the stream of CGANF bubbles increased as more CGANF fluid was injected. Also, the lamella division mechanism generated more small bubbles resulting in increasing differential pressure across porous micro-models. Contrasted to bigger CGANF bubbles, smaller CGANF bubbles had lesser movability. Therefore, they were key factors for blocking pores and throats of porous media and changed the orientation of bigger bubbles in cracks toward the matrix. Observations revealed that CGANF micron-bubbles built up through the porous media could set up an impressive snag to control loss of filtrate, and permeability of models was reverted almost to its primary permeability when saturation fluid was reinjected into micro-models. For the detailed analysis in this study, the maximum percentages of reverted permeability for fractured and un-fractured non-uniformed micro-models were attained 91.81% and 90.70%, respectively. Also, by increasing XG concentrations from 0.286 to 0.571% w/v, return permeability percentage increased from 84.4% to 87.4%. There was an optimum concentration of nanoparticles at 0.0571% w/v of silica and fumed silica, and consequently, returned permeability and infusion pressure of CGANF fluid reached their maximum values. Moreover, the stability of the CGANF fluid increased to 8.15% and 12.6% by adding silica and fumed silica nanoparticles, respectively, to the CGA fluid formulation without nanoparticles. This article presents a novel insight into porous media for analyzing blockage capability and controlling porous media damage created via CGANF-based fluids in non-uniformed environments. • Enhancing the behavior and properties of CGANF fluids. • Use of silica and fumed silica nanoparticles in CGANF fluids. • Controlling filtration loss by forming an effective seal using CGA/CGANF fluids. • Use of heterogeneous transparent glass micromodels for monitoring the bubbles flowin the pores and fracture by microscope. • Analysis of return permeability by high accurate pressure drop data through micromodel.

Preparation and in vitro characterization of electrospun scaffolds composed of chitosan, gelatin and 58S bioactive glass nanoparticles for skin tissue engineering

Background and aims: The presence of an appropriate scaffold at the wound site could significantly improve the healing process. In this study, we aimed to prepare a biomimetic nanocomposite scaffold composed of chitosan, gelatin, and 58S bioglass nanoparticles for skin tissue engineering. Methods: The nanocomposite scaffolds composed of chitosan, gelatin, and 58S bioglass nanoparticles were fabricated through electrospinning process. Then the cell viability assay was performed in order to evaluate the biological properties of the membranes. The optimum concentration of bioglass nanoparticles was determined for further studies. In vitro characterization was also performed to evaluate physicochemical properties of the scaffolds. Results: The chitosan/gelatin scaffold containing 2% of 58S bioglass nanoparticles showed no cell toxicity, and the dermal fibroblasts were found capable of proliferation on the membrane. The in vitro results obtained from the scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and porosity tests demonstrated the appropriate properties of the membrane as a scaffold for skin regeneration. Conclusions: It was concluded that a chitosan-gelatin membrane containing 2% of 58S bioglass nanoparticles had the potential to function as a scaffold to accelerate wound healing due to its suitable properties, such as high porosity, high surface/volume ratio, and excellent biocompatibility.

Temperature effects on anionic/nonionic surfactant mixture and silica nanofluid dispersion for foam-EOR

Foam-assisted gas has been widely employed in enhanced oil recovery (EOR) by improving the volumetric sweep efficiency gas mobility of injected gas. However, the major obstacle of foam-assisted gas EOR is maintaining foam lamellae’s stability, especially in harsh reservoir conditions. As mentioned above, the study focused on the effect of silica nanoparticles (SiO2 NPs) in an anionic/nonionic surfactant mixture in enhancing the stability of foam film. The optimum concentration of silica nanoparticles was determined through various experimental approaches. The surface tension and interfacial tension in the presence and absence of SiO2 NPs were measured and recorded. The Bartsch shaking method was applied to analyse the foam half-life and foam static stability. Anionic surfactant Sodium Dodecyl Sulfate (SDS) was utilised with the nonionic surfactant Triton X100 (TX100) at a ratio of 4:1. Addition of various concentration (0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt% and 1.0 wt%) SiO2 NPs in two surfactant mixtures. The screening method was utilised to determine the optimum concentration of SiO2 NPs in SDS-TX100 surfactant mixture at 25 °C and 70 °C. The optimisation from the screening process demonstrated 0.4 wt% SiO2 NPs was suitable in SDS-TX100 surfactant mixture for stabilising the foam films.

Heat transfer and flow visualization of pulsating heat pipe with silica nanofluid: An experimental study

As heat transfer device with two-phase flow, pulsating heat pipe (PHP) has a widely application prospect in the fields of improving energy efficiency and thermal management. In order to optimize the heat transfer performance of PHP, a visualization experiment was carried out with a high-speed camera, and detailed characteristics of flow pattern variations in nanofluid PHP were obtained. The effect of SiO2-H2O nanofluid with different concentrations (0.5 wt%, 1.0 wt%, 1.5 wt% and 2.0 wt%) were experimentally investigated to analyze the thermal performance of PHP. Results demonstrate that the addition of nanoparticles on the one hand promotes the phase transition of the working fluid in the PHP, and on the other hand increases the instantaneous velocity and the driving force of working fluid. These are all benefit for the reflux of condensed liquid and effectively avoid the phenomenon of ′dry out′. Additionally, the results also indicate that there exists an optimum concentration of dispersed nanoparticles in base fluid to enhance heat transfer. The maximum heat transfer enhancement efficiency with nanofluid concentration of 1.0 wt% can reach 40.1 % at the heating power of 50 W. The present results can provide useful inspiration for the development and application of new type pulsating heat pipe.