Conductivity Of Ethylene Glycol Research Articles

Optical, dielectric, and rheological properties of EG-Al2O3/AgNO3 nanofluids: Insights and advances in multifunctional materials for soft device technologies

Nanofluids (NFs) of fascinating multifunctional properties are the advanced materials highly admired in emerging soft device technologies. In this innovative research, we explored the detailed optical, dielectric, and rheological properties of silver ions conducting green NFs. These NFs comprise ethylene glycol (EG) as viscous base fluid, suspension of a fixed amount (0.02 wt%) aluminum oxide (Al2O3) nanoparticles for high performance thermal conductor, and addition of silver nitrate (AgNO3) salt as the ionic component of varying amounts ranging from 0.2 to 2.0 wt% are prepared and investigated. The detailed analysis of 200–800 nm wavelength range ultraviolet–visible (UV–Vis) absorbance spectra of these EG–Al2O3/AgNO3 based NFs demonstrated their significant photosensitivity character in the visible region, radiations shielding performance in the UV region, and trio energy band gaps in a wide semiconducting range from 2.4 to 4.9 eV which are found adequately tunable with the AgNO3 concentrations. The high static dielectric permittivity (εs ≈ 40) of these polar NFs, at 298.15 K, showed a marginal change with the variation in AgNO3 concentrations confirming a little alteration in the parallel aligned dipole ordering of hydrogen bonded EG molecular network beside the ion-molecules-nanoparticle interactions and formation of ion-dipole complexes (coordinative interaction). The electrical conductivity of EG–Al2O3 NF increased by three orders of magnitude i.e., from 10−6 to 10−3 S/cm, at the initial addition of 0.2 wt% AgNO3 in it and then, exhibited almost a linear increase with further increasing the salt concentrations up to 2.0 wt% realizes them promising ionic nanofluids. Rheological investigations on these NF samples, at 298.15 K, validate their Newtonian behaviour with a high dynamic viscosity of 14 mPa s. These experimental findings highlight the multifunctional characteristics of EG–Al2O3/AgNO3 nanofluids which could be utilized in heat transfer, solar energy harvesting/storage, and the development of next-generation iontronic and optoelectronic devices and silver ion conducting biomedical sensors.

Measurement and modeling of thermal conductivity of graphene nanoplatelet water and ethylene glycol base nanofluids

Three graphene nanoplatelet (GNP) nanofluids with different base fluids, viz. ethylene glycol (EG), deionized water (DW), and EG/DW (1:1) were prepared and characterized. The stability of GNP nanofluid was analyzed. Thermal conductivity was tested over the temperature range −20 °C to 50 °C. A new model is proposed for the effective thermal conductivity of the GNP nanofluid considering Brownian motion, length, thickness, average flatness ratio and interfacial thermal resistance of GNP, and it was compared with Maxwell, H-C and Chu models. The maximum thermal conductivity enhancement of EG, EG/DW (1:1) and DW based nanofluid is 4.6%, 18% and 6.8% respectively. Interestingly, the thermal conductivity of EG based GNP nanofluids does not show appreciable enhancement. The thermal conductivity enhancement of EG/DW (1:1) GNP nanofluid is greater than that of pure EG GNP nanofluid. In particular, the enhancement ratio at subzero temperature is larger than that at higher temperatures. The new model and Chu model are in agreement with the experimental data, and the new model is more rational for the GNP nanofluids. The new model shows that the influence of Brownian motion of GNP on thermal conductivity is significant at higher temperatures, higher concentration and smaller nanoparticles.

Experimental evaluation, new correlation proposing and ANN modeling of thermal properties of EG based hybrid nanofluid containing ZnO-DWCNT nanoparticles for internal combustion engines applications

Thermal conductivity of EG based hybrid nanofluid containing ZnO-DWCNT nanoparticles was investigated experimentally at concentration of 0.045 to 1.9% and a temperature of 30–50 °C. ZnO particles (with an average diameter of 10–30 nm) and double wall carbon nanotubes (DWCNT) (internal diameter of 3–5 nm and 5–15 nm external diameter) were mix at a ratio of 90%: 10% and dispersed in ethylene glycol (EG) then its thermal conductivity was measured. The results showed that maximum relative thermal conductivity (TCR) at temperature of 50 °C and the concentration of 1.9%, equivalent to 24.9%. Economic evaluation and qualitative performance showed that nanofluids hybrid compared with ZnO and nanofluids containing MWCNT, in terms of increasing thermal conductivity (TCE) and economically, is quite effective. A new correlation to predict TCR in terms of concentration of nanoparticles and the temperature was proposed. This correlation has a coefficient of determination (R-squared) and the maximum error of 0.9826 and 2.9%, respectively. The greatest sensitivity was calculated at a maximum temperature and solid volume fraction. Based on the TCR data the artificial neural network (ANN) was developed. The best case ANN containing two hidden layer and 3 neurons in each layer was obtained. This ANN has an R-squared and MSE and was equal to 0.9966% AARD and 1.3127e-05 and 0.0489, respectively. The comparison between experimetnal data, correlation and ANN outputs shows the accuracy and capability of ANN in modeling the TCR data.

Electrical Conductivity of Ethylene Glycol Based Nanofluids with Different Types of Thulium Oxide Nanoparticles

Electrical Conductivity of Ethylene Glycol Based Nanofluids with Different Types of Thulium Oxide Nanoparticles

Investigate the effects of EG doping PEDOT/PSS on transmission and anti-reflection properties using terahertz pulsed spectroscopy

The conductivity of poly(3,4-ethylene dioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) is significantly enhanced on adding some organic solvent such as ethylene glycol (EG). In this paper, the optoelectronic properties of EG doped PEDOT/PSS on transmission and anti-reflection effects are investigated in detail by terahertz time domain spectroscopy (THz-TDS). The transmission line circuit theory gives us an insight into the THz transmission mechanisms of the main and second pulses. In particular, we show that the conductivities of 10% EG doped PEDOT/PSS are nearly frequency independent from 0.3 to 1.5 THz. To demonstrate applications of this property, we design and fabricate broadband terahertz neutral density filters and anti-reflection coatings based on 10% EG doped PEDOT/PSS thin films with varying thickness. Our measurements highlight the capability of THz-TDS to characterize the conductivity of EG doped PEDOT/PSS, which is essential for broadband optoelectronic devices in THz region.

Experimental study on thermal conductivity of ethylene glycol containing hybrid nano-additives and development of a new correlation

In this paper, an experimental investigation on the effects of hybrid nano-additives, composed of magnesium oxide (MgO) and functionalized multi-walled carbon nanotubes (FMWCNTs), on the thermal conductivity of ethylene glycol (EG) is presented. The experiments performed at temperatures ranging from 25°C to 50°C and the solid volume fraction range of 0–0.6%. The measurements revealed that the thermal conductivity of nanofluids significantly enhances with an increase in the percentage of the solid volume fraction. Moreover, the thermal conductivity of EG considerably increased with increasing temperature, while thermal conductivity of hybrid nanofluid slightly enhanced. The thermal conductivity measurements showed that the maximum enhancement of thermal conductivity of nanofluid is 21.3%, which occurred at solid volume fraction of 0.6% and temperature of 25°C. Finally, efforts were made to provide an accurate correlation for estimating the thermal conductivity at various temperatures and concentrations. Deviation analysis of the thermal conductivity ratio was performed. The comparison between experimental results and correlation outputs showed a good agreement.

An Experimental Investigation into the Thermal Properties of Nano Fluid

In this paper, the results of the experimental investigation on the thermal properties of Nano fluid are presented. The effect of sonication time, settling time and temperature on the thermal conductivity, viscosity and specific heat of zinc oxide (ZnO, 14 nm and 25 nm size) and single walled carbon nanotube (SWCNT, 10nm size) based Nano fluid are investigated and the results of ZnO with DI water and ethylene glycol (EG) as base fluids are compared. The experimental results indicate that the studied parameters have a remarkable effect on the thermal properties of Nano fluid. The rate of enhancement in thermal conductivity of EG based Nano fluid is found to be less than that of water based Nano fluid. The SWCNT based DI water Nano fluid found to be very unstable i.e. the nanoparticles settle down very rapidly. The 0.02% volume fraction of SWCNT nanoparticles suspension results in 10% increase in the specific heat of DI water. A decrement of 24% and 13% in the specific heat of 14 nm size ZnO based Nano fluid were obtained at a volume fraction of 0.001% and 0.002% respectively.

Coupled molecular dynamics-stochastic model for thermal conductivity of ethylene glycol based copper nanofluid.

A coupled molecular dynamics (MD)-stochastic simulation based model has been proposed here for the thermal conductivity of ethylene glycol (EG) based copper nanofluid. The model is based on the thermal evolution of the nanoparticles dispersed in the nanofluid which is in contact with a heat source. It is natural that the nanoparticles dispersed in the nanofluid would move randomly by Brownian motion and repeatedly collide with the heat source. During each collision the nanoparticles would extract some heat by conduction mode from the heat source and this heat would be dissipated to the base fluid during Brownian motion by a combination of conduction and microconvection mode. Thus, in addition to normal conductive heat transfer through the base fluid (EG) itself (without nanoparticles) some amount of heat is transferred by the collision of the nanoparticles with the heat source. The extent of this additional heat transfer has been estimated in the present model to estimate the enhancement in thermal conductivity of EG based copper nanofluid, as a function of volume fraction loading of nanoparticles. The prediction of the present model has been compared with the experimental data available in literature, and it has shown a reasonable agreement between the theoretical prediction and the experimental data.

Benefits of dispersion solvents with more OH groups in electrospray preparation of TiO2 photoelectrode for the improvement of DSSC performance

TiO2 anode prepared by electrospray (ES) method using dispersion solvents of ethylene glycol (EG) or glycerol enhanced the performance of dye-sensitized solar cells (DSSCs) compared to the conventional solvent of ethanol. TiO2 dispersion in EG or glycerol were found more stable as demonstrated by dynamic light scattering (DLS) experiments. Infrared spectra (IR) revealed that dispersion solvent with more hydroxyl (OH) groups could interact with TiO2 more effectively, leading to higher stability of TiO2 suspension, and enabling higher TiO2 concentration, which are beneficial to mass production by utilizing stable suspension as well as reducing deposition time. When ethanol is used as dispersion solvent, the nozzle is often clogged by TiO2 block due to fast evaporation of ethanol at the nozzle tip. When EG and glycerol are used, this problem does not appear because of their nonvolatile nature. In addition, higher conductivity of EG and glycerol also helps to generate smaller droplet in ES process, thus more uniform TiO2 films is expected. Scanning electron microscope (SEM) study showed that while hierarchically structured TiO2 (HS-TiO2) spheres were formed in TiO2 anode by ES deposition using any one of three solvents, the secondary grain sizes of TiO2 in the EG and glycerol based anodes were bigger. As a result, better DSSC performance was achieved based on TiO2 anode prepared by ES procedure using dispersion solvent of glycerol under high TiO2 concentration.

Investigation of Thermal Conductivity and Viscosity of Carbon Nanotubes–Ethylene Glycol Nanofluids

Conventional fluids used for heat transfer applications in automobiles limit the performance enhancement and compactness of the heat exchangers. These problems can be overcome by using the technology of nanofluids. The objectives of this work are to prepare nanofluids and to study their dynamic viscosity and thermal conductivity. Chemically treated carbon nanotubes (CNTs) were added with ethylene glycol (EG) and sonicated using a bath sonicator to have a homogeneous dispersion of CNTs in EG. In this study, the nanofluids were prepared with different concentrations of CNTs varying from 0.12 to 0.4 wt%. The dynamic viscosity of nanofluids was measured using a rheometer over a temperature range of 25°C to 60°C. It was observed that the viscosity of nanofluids decreases with an increase of temperature and enhances with CNT concentration. The nanofluid follows the characteristic behavior of Newtonian fluids. A linear rise in thermal conductivity of ethylene glycol was observed with an increase of CNT concentration. It is concluded that EG–CNT nanofluids are promising to meet the challenges required by automobile systems.

Surfactant free graphene nanosheets based nanofluids by in-situ reduction of alkaline graphite oxide suspensions

Herein we report an entirely different route for the synthesis of graphene nanosheets (GNs) based nanofluids without surfactant or harsh chemical treatments, by reducing the alkaline graphite oxide suspension in ethylene glycol (EG) and de-ionized (DI) water based fluids by a simple thermal treatment. The thermal conductivity measurement after the reduction shows about 6.5 and 13.6% enhancements at 25 °C for the 0.14% volume fraction of GN in EG and DI water, respectively, which is ascribed to the high aspect ratio of the GNs. In addition, a large enhancement in the electrical conductivity of EG and DI water based reduced nanofluids is observed. This interesting result is attributed to the high electrical conductivity of reduced graphene nanosheets suspensions.