Water Glycol Research Articles

Design and testing of the supporting setup for the high-pressure vibrating tube densimeter

Vibrating tube densimeters (VTDs) have become relatively popular instruments for measuring the density of a large variety of gases and liquids since their development about fifty years ago. The apparatuses measure the characteristic frequencies of vibrating U-shaped tube filled with a fluid sample, when the fluid fill shifts the dynamic characteristics of the U-tube. This study describes design and testing of the in-house developed supporting setup for a commercial high-pressure VTD Anton Paar DMA HP. The instrument covers density range from 0 to 3000 kg/m3 at pressures up to 700 bar and temperatures from -10 to 200 °C. Whereas the temperature of density measurement is fully controlled by the apparatus using a thermal block with Peltier unit, pressure has to be generated and monitored externally. Therefore, a high-pressure sampling system was designed and assembled. Special care is taken when measuring temperature with an external resistance thermometer connected to precise thermometry bridge. In order to avoid unfavorable condensation of air moisture during the measurement, VTD apparatus is protected by a dry box of own design. Technical details together with the calibrations of pressure and temperature probes are described in detail. A preliminary data for temperature dependence of density of the selected liquids (water, ethanol or ethylene glycol) obtained at the barometric pressure are also provided and compared to the reference density correlations.

Molecular Dynamics Simulations of the Microscopic Mechanism of Thermal Conductivity Enhancement of Ethylene Glycol–Water–Au Nanofluids

Molecular Dynamics Simulations of the Microscopic Mechanism of Thermal Conductivity Enhancement of Ethylene Glycol–Water–Au Nanofluids

Entropy generation analysis in a gasket plate heat exchanger using non-spherical shape of alumina boehmite nanoparticles

Abstract The analysis deals with the thermo-hydraulic performance of a Gasket Plate Heat Exchanger used for cooling vegetable oils with a water-ethylene glycol 50% and volume fractions of non-spherical nanoparticles mixture as a refrigerant. The heat exchanger has 75 plates with a chevron angle equal to 30º. The Reynolds number of the refrigerant varies from 80 to 1530. The Reynolds number of the sunflower vegetable oil is fixed and equal to 30. The non-spherical nanoparticles used for analysis are platelet, cylindrical and brick types. Graphical results are presented for global heat transfer coefficient, heat capacity ratio, heat transfer rate, outlet temperatures, thermal and viscous entropy generation rate, and Bejan thermodynamic number. The results obtained allow us to conclude that it is possible to work with low relative flow rates using non-spherical nanoparticles, emphasizing platelet nanoparticles. The entropy generations analysis shows that very high flow rates of the refrigerant dissipate much of the energy in viscous form and do not contribute to oil cooling, with a consequent increase in the heat exchanger operating costs.

Heat transfer studies of Al2O3/water-ethylene glycol nanofluid using factorial design analysis

The experimental study of the heat transfer coefficient of nanofluid plays a significant role in improving the heat transfer rate of the heat exchanger. A natural convection apparatus was used to study heat transfer in the suspension of Al2O3 nanoparticles in a water-ethylene glycol mixture base fluid. The effects of the heat input, the nanoparticle volume fraction, and the base fluid concentration on the heat transfer coefficient were studied using a 23 full factorial design matrix (16 experimental runs) and the MINITAB Design software. The levels for the heat input, nanoparticle volume fraction, and base fluid concentration were 10 and 100 W, 0.1 and 1 vol.%, and 30 and 50 vol.%, respectively. The residual, contour, 3D surface plots, and Pareto chart were drawn from the experimental results. The observed heat transfer coefficient showed the highest enhancement with the high level of the nanoparticle volume fraction and a moderate enhancement with the high level of heat input, and a slight enhancement with the base fluid concentration.

Two Step Cost-Saving Process for Industrial Scale Production of 1-Amino-3,5-dimethyladamantane Hydrochloride (An Anti-Alzheimer’s Drug)

This work presents a predominant cost-saving process for the industrial scale synthesis of memantine hydrochloride (1) from 1,3-dimethyladamantane (2) by a two-step method in which both steps were carried out in one-pot. The conversion of 2 to N-(3,5-dimethyladamantane-1-yl)acetylamide (3) was synthesized first in mixture of sulfuric acid 96-98% and nitric acid 64-65% at 25 ºC for 2.5 h and then in acetonitrile at 40 ºC for 3.5 h as a key step. The yield of this process reached to 98%. Next, the deacetylation of 3 with potasium hydroxide in mixture of water-ethylene glycol at 140 ºC for 15 h to get memantine base which was then converted into memantine hydrochloride (1) by aq. HCl 14% (yield of 93%). Overall yield of this synthetic route was 91.65%. The advantages of this process is saving time, solvents, reagents and giving a higher yield as compared to reported procedures.

Binary mixture droplet wetting on micro-structure decorated surfaces

Liquid surface tension as well as solid structure play a paramount role on the intimate wetting and non-wetting regimes and interactions between liquids droplets and solid substrates. We hypothesise that the coupling of these two variables, independently addressed in the past, eventually offer a wider range of understanding to the surface science and interfacial communities.In this work, intrinsically hydrophobic micro-pillared surfaces varying in the spacing between structures, and pure ethanol, pure water and their binary mixtures (as well as acetone–water and ethylene glycol–water mixtures) are utilised, accessing a wide range of substrate solid fractions and liquid surface tensions experimentally. Wettability measurements are carried out at different azimuthal directions to exemplify the wetting/non-wetting behaviour as well as the droplet asymmetry function of both liquid composition and structure spacing.Our findings reveal that high water concentration droplets, i.e., high surface tension fluids, sit in the Cassie-Baxter regime while partial non-wetting Wenzel or mixed-mode regimes with enhanced droplet asymmetry ensuing for medium and high ethanol concentrations, i.e., low surface tension fluids, below certain micropillar spacing. Beyond micropillar spacing s ≥ 40 µm, the impact of the surface structure on the droplet shape is negligible, and droplets adopt a similar contact angle and circular shape as on a flat smooth hydrophobic surface. Wetting and non-wetting regimes are then supported by classical wetting theories and equations. A wetting regime map for a wide range of surface tension fluids and/or their mixtures on a wide domain of solid fractions is then proposed.

Study on energy saving of heat integrated distillation process for methyl acetate–methanol–tetrahydrofuran–water

ABSTRACT Based on the characteristics of binary azeotropic composition in the mixture of methyl acetate–methanol–tetrahydrofuran–water sensitive to pressure, pressure swing distillation (PSD) and double-solvent extraction distillation (DSED) were proposed to study the separation of the quaternary system. Numerical simulations were performed by ASPEN PLUS software (version 10.0) environment under the WILSON thermodynamic model. The economy of PSD and DSED process was performed, and the heat integration of two distillation processes was compared based on total annual cost (TAC). Research results of PSD indicated that compared with conventional PSD (CPSD), heat-integrated PSD (HIPSD) can save energy consumption and TAC by 33.87% and 30.70%, respectively, and moreover increase thermodynamic efficiency by 1.77%, so it had obvious energy-saving effect and economic advantage. Simulation results of DSED showed that water (H2O) and ethylene glycol (EG) were most suitable extractants for the system, and the suitable solvent ratios for H2O and EG were 0.28 and 0.38, respectively. Compared with conventional double-solvent ED (CDSED), heat-integrated double-solvent ED (HIDSED) can save energy consumption and TAC by 43.29% and 28.12%, respectively, and moreover increase thermodynamic efficiency by 3.25%, so it was superior to CDSED. The results indicated that the energy consumption and TAC of HIDSED are respectively 63.56% and 44.01% less than the HIPSD process, and the thermodynamic efficiency of the former is 3.9% larger than the latter, so the HIDSED process shows better economic and energy-saving effect.

Characterisation, Performance and Optimisation of Nanocellulose Metalworking Fluid (MWF) for Green Machining Process

The present research attempts to develop a hybrid coolant by mixing alumina nanoparticles with cellulose nanocrystal (CNC) into ethylene glycol-water (60:40) and investigate the viability of formulated hybrid nanocoolant (CNC-Al2O3-EG-Water) towards enhancing the machining behavior. The two-step method has been adapted to develop the hybrid nanocoolant at various volume concentrations (0.1, 0.5, and 0.9%). Results indicated a significant enhancement in thermal properties and tribological behaviour of the developed hybrid coolant. The thermal conductivity improved by 20-25% compared to the metal working fluid (MWF) with thermal conductivity of 0.55 W/m℃. Besides, a reduction in wear and friction coefficient was observed with the escalation in the nanoparticle concentration. The machining performance of the developed hybrid coolant was evaluated using Minimum Quantity Lubrication (MQL) in the turning of mild steel. A regression model was developed to assess the deviations in the tool flank wear and surface roughness in terms of feed, cutting speed, depth of the cut, and nanoparticle concentration using Response Surface Methodology (RSM). The mathematical modeling shows that cutting speed has the most significant impact on surface roughness and tool wear, followed by feed rate. The depth of cut does not affect surface roughness or tool wear. Surface roughness achieved 24% reduction, 39% enhancement in tool length of cut, and 33.33% improvement in tool life span. From this, the surface roughness was primarily affected by spindle cutting speed, feed rate, and then cutting depth while utilising either conventional water or composite nanofluid as a coolant. The developed hybrid coolant manifestly improved the machining behaviour.

The influence of temperature on physical properties of a hybrid nanofluid flow in a non-Darcy porous medium

The purpose of this paper is to debate the influences of variable thermal conductivity as well as viscosity on a hybrid nanofluid flow through a non-Darcy porous medium along a wavy surface. Two kinds of base fluids are considered; the first is water (H2O) with [Formula: see text] and the second is ethylene glycol–water mixture (C2H6O[Formula: see text]H2O) with [Formula: see text]. Furthermore, the physical properties of the base fluid have been modified via the addition of two kinds of suspended nanoparticles. The suspended nanoparticles of alumina Al2O3were firstly added to the base fluid. Then, titania TiO2suspended nanoparticles are immersed into this nanofluid to form two hybrid nanofluids (TiO[Formula: see text]Al2O3/H2O) and (TiO2-Al2O3/C2H6O2–H2O). Dupuit Forchheimer model as a non-Darcy porous medium is utilized. The mathematical model for the present physical problem with convective boundary condition is studied numerically via the Chebyshev pseudospectral (CPS) technique. Nusselt number, velocity and temperature profiles are investigated under different parameters. The present outcomes clarify that adding the alumina nanoparticle supports and improves the efficiency of the titania nanoparticle. Also, taking both of the hybrid nanofluid viscosity/thermal conductivity as variable functions of temperature has an important role to support the studies of heat transfer.

In Vitro Wound Dressing Stack Model as a First Step to Evaluate the Behavior of Dressing Materials in Wound Bed-An Assessment of Mass Transport Phenomena in Hydrogel Wound Dressings.

Wound dressings when applied are in contact with wound exudates in vivo or with acceptor fluid when testing drug release from wound dressing in vitro. Therefore, the assessment of bidirectional mass transport phenomena in dressing after application on the substrate is important but has never been addressed in this context. For this reason, an in vitro wound dressing stack model was developed and implemented in the 3D printed holder. The stack was imaged using magnetic resonance imaging, i.e., relaxometric imaging was performed by means of T2 relaxation time and signal amplitude 1D profiles across the wound stack. As a substrate, fetal bovine serum or propylene glycol were used to simulate in vivo or in vitro cases. Multi-exponential analysis of the spatially resolved magnetic resonance signal enabled to distinguish components originating from water and propylene glycol in various environments. The spatiotemporal evolution of these components was assessed. The components were related to mass transport (water, propylene glycol) in the dressing/substrate system and subsequent changes of physicochemical properties of the dressing and adjacent substrate. Sharp changes in spatial profiles were detected and identified as moving fronts. It can be concluded that: (1) An attempt to assess mass transport phenomena was carried out revealing the spatial structure of the wound dressing in terms of moving fronts and corresponding layers; (2) Moving fronts, layers and their temporal evolution originated from bidirectional mass transport between wound dressing and substrate. The setup can be further applied to dressings containing drugs.

Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability

Objectives: The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC). Materials and methods: Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM. Results: The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste. Conclusions: All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results. Clinical relevance: Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Dielectric constant of mixed solvents based on perturbation theory

Industrial applications such as batteries and bio-separations require modeling the thermodynamic properties of mixed solvent electrolytes. Thermodynamic models for electrolytes often consider the solvents as a dielectric continuum characterized by their dielectric constant. Therefore, accurate predictions require a physically sound model for the dielectric constant of mixed solvents, depending on temperature, pressure, and mixture composition. We present a physical model for the dielectric constant of pure solvents and mixtures based on perturbation theory. The analytical expression is third order in the dipole density. For each pure component, the model requires the dipole moment and two adjustable pure-component parameters. We apply the model to the binary mixtures methanol–water and ethylene glycol–water considering pure component experimental data for temperatures between 273.15 K to 823.15 K and pressures between 0.1 MPa and 1189.0 MPa. The presented model improves the prediction of the mixed solvent dielectric constant for both mixtures compared to the linear molar mixing rule, and achieves similar accuracies as the linear volume-based and mass-based mixing rules. We show that the model is suitable in the case of scarce experimental data.

Protective effect of Urtica dioica in liver and kidney damages induce by ethylene glycol in rabbits: A histopathological study

Urtica dioica is used in the many countries as seasoning and as an herbal medicine (antioxidant). In this study, adult male locale rabbit was separated into five groups, Group 1 considered as control, Group 2 to 5 animals were treated with 0.75% ethylene glycol (EG) in water to induce renal and liver damage till 30th day. The group 3 to 5 animals were feed extract of the plant of U. dioica at a dosage of 100 mg/kg body weight from day 15 to the day 30. The extracts were administered twice daily orally. Liver histopathological changes characterized by vacuolar degeneration and coagulative necrosis of hepatocytes, congestion and dilatation of central vein and sinusoids. Renal histopathological changes characterized by deposition of oxalates, blood vessels congestion infiltration of inflammatory cells and change in renal glomeruli in GE treated groups. While histopathological changes in the animals group treated with U. dioica extract and ethylene glycol showed an increase improvement of the histological features of liver tissue, were limited dilatation of renal tubules with less deposition of oxalates, as well as slight infiltration of inflammatory cells in the interstitial tissue. Finally, as a conclusion we noticed that U. dioica extracts had the ameliorative effect of ethylene glycol-induced hepatic and renal histopathological.

Comparison of Heat Transfer rates for Water and Ethylene Glycol mixtures for Diesel engine exhaust gas heat recovery using Shell and Tube Heat Exchanger.

Most of the researchers have claimed that high compression engines (diesel engines) are performing slightly above of 1/3rd of their potential and remaining heat energy is wasted in the form of exhaust gas. Efforts are going on to improve the design of these engines and investigations are being carried out to recover this waste energy from exhaust gases and utilize for different applications.In the present work, initially water is used as a heat exchange medium for three different loads on diesel engine viz., 50%, 60% and 70%, which extracts heat energy to evaluate the exhaust heat attainable from exhaust gases of the engine. The exhaust gas is passed through the tube side of the heat exchanger which is obtained from an exhaust manifold of a four stroke single cylinder diesel engine. Water is passed through the shell side of the shell and tube heat exchanger. Later this work is repeated for two different cooling medium i.e. water-ethylene glycol mixtures with 25% and 50%. The results are compared for 60% engine load conditions. The counter flow type heat exchanger arrangement is considered for the analysis. The temperatures were recorded for hot gases and cold medium at inlet and outlet points of the shell side and tube side flow. Heat calculations are carried out for each combination and detailed in the result–discussion and conclusion chapter. The objective of this work is to assess the exhaust gas heat recovery capacity using the ethylene glycol-water mixture and come out with a mixture for higher heat recovery capacity. This work is undertaken with segmental baffle heat exchanger of zero degree inclination. Also the work is repeated for inclined baffle heat exchangers of 10-degree and 20-degree baffle inclination to assess the effectiveness of liquid in recovering the heat from exhaust gases. It is observed that the water and Ethylene glycol mixtures have performed satisfactorily in all three baffle setups showing only 1.5% - 2.0% less heat recovery when compared with only water.

Characteristics of Sargassum plagyophillum Extract as An Active Compound on Non-Alcoholic Hand Sanitizer

Excessive use of non-alcoholic hand sanitizers irritate to the skin, moreover a burning effect, that alternative natural active compound is required, namely Sargassum plagyophillum extract. S. plagyophillum extract contains secondary metabolites that can act as antibacterial and can moisturize the skin. This research aimed to determine the microbiological and physical characteristics of S. plagyophillum of the non-alcoholic hand sanitizer. The sample used in this research was 2% S. plagyophillum extract obtained by maceration using methanol. The production of non-alcoholic hand sanitizers was conducted using other ingredients such as carbopol, triethanolamine, methyl paraben, propilen glycol, and distilled water. The test parameters were testing for gram-positive and gram-negative antibacterial activity, pH, and viscosity. The results showed that non-alcoholic hand sanitizer containing 2% S. plagyophillum extract had characteristics in the form of a gel with gram positive antibacterial activity (Listeria monocytogenes) with an inhibition zone of 2.50 mm, while gram negative antibacterial activity (Pseudomonas aeruginosa) with an inhibition zone of 4.33 mm. Subsequently, the pH value produced from the hand sanitizer containing S. plagyophillum was in accordance with recommended skin pH of 7.33. Meanwhile, based on the value of the viscosity, the hand sanitizer containing S. plagyophillum had a viscosity value according to the viscosity standard, namely 2600 cPs.

Phase equilibrium in the ternary system water–ethylene glycol–dimethyl sulfoxide

The ternary system water–ethylene glycol–dimethyl sulfoxide (H2O–EG–DMSO) was investigated by differential scanning calorimetry in the temperature range of 188–298 K. In the concentration range from ∼10 to ∼50 mol% DMSO, crystallization or glass formation are not observed when the temperature is lowered to 188 K. Significant supercooling of the solution in this composition range is explained by the existence of spatial networks of H2O and EG.

Precise determination of R134a boiling bundle effect on a column of reentrant cavity tubes

The boiling bundle effect was investigated on a column of reentrant cavity tubes to reveal the heat transfer coefficient (HTC) variation for a tube which is affected by other tubes. All experimental data were obtained on the specific tube, which is the distinct difference between the adopted homologous method and the routine method. Two columns of eight horizontal tubes were submerged in R134a liquid, and each tube was specifically heated by an ethylene glycol–water mixture. The saturation temperature was 6.0 °C, the heat flux ranged from 10.0 kW/m2 to 28.0 kW/m2, and the row number ranged from 1 to 7. The tube length in the test section was 500 mm, and the pitch–diameter ratio was 1.32. Results showed that the uncertainty of the bundle effect using the homologous method was less than ± 4.4%, which decreased by at least 80% compared with that using the routine method. The values were from 1 to 1.32, indicating that the upward bubbles from the lower heated tubes positively influenced the boiling HTC. Moreover, the bundle effect increased with the increase in row number and decreased with the increase in heat flux. Correlations of the single-tube HTC and the bundle effect with vapor film Reynolds number and effective row number were established to predict the experimental data. The current study can offer a reference for further investigations of film or convective boiling on tube bundles.

Experimental and Numerical Study of Thermal Performance for Flat Plate Solar Water Heater in Najaf

This work presented the numerical and experimental study of the thermal performance of a flat plate collector (FPC). This study focuses on analyzing the performance of (FPC) in the climatic conditions of Najaf and calculating the thermal energy produced by the collector for domestic use, which reduces the electricity consumption that Iraq is witnessing a severe shortage in its supply. Also, various working fluids (water, oil engine, ethylene glycol-water mixture) were tested to determine the best working fluid that improves the collector’s efficiency. The experiments were performed in Najaf, Iraq (32° 2’ N / 44° 18’ E) on January 9, 2019. The simulation study of the (FPC) is performed by COMSOL Multiphasic 5.3 software. The numerical results were validated with experimental results and there was good convergence between them. The results showed that the average daily efficiency of the solar collector (FPC) was 37.17%, and the highest outlet water temperature of the collector was 57.1Co. The collector achieved a useful cumulative useful heat during the day of about 3.3557 MW, this contributes to reducing the use of electricity and achieving the required economic feasibility of use (FPC). Finally, the engine oil gave better results in improving efficiency compared to other working fluids.

An insight into the performance of radiator system using ethylene glycol-water based graphene oxide nanofluids

Recent studies showed that nanofluids are considered as a promising way to enhance the heat transfer properties of coolants. Currently, in a car radiator forced convection heat transfer method is carried out to cool circulating fluid. The mixture of water with either ethylene or propylene-glycol is necessary to lower its freezing point and eliminate ice formation. However, the boiling point of deionized water can be pushed up by mixing it with anti-freezing materials like ethylene glycol (EG). Hence the present research work focuses on the heat transfer characteristics of nano-fluids with different combinations of EG and deionized water (60:40, 30:70, and 20:80) along with graphene oxide (GO) nanoparticles (0.1 % wt). The heat transfer potential of graphene oxide/ deionized water-ethylene glycol nanofluids is experimentally investigated in coolant application for car radiators, in which the coolant flow rate is varied from 180 to 420 (LPH) at a fixed coolant temperature of 90 °C. The evaluation of stability is performed using visual inspection and zeta potential test. The density of nanofluid was determined by oscillating U-Tube density meter. The optimized combination of 60% EG, 40% DW and 0.1 wt% GO exhibited higher heat transfer characteristics of the radiator system used. The maximum heat transfer enhancement of 42.77% at 300 LPH, 18.14% at 360 LPH, and 71.1% at 240 LPH for 60:40 EG/DW-based GO nanofluids were obtained. The maximum Nusselt number value of 192 at 420 LPH was observed for 60:40 EG/DW-based GO nanofluid as compared with 20:80, 30:70 EG/DW-based GO nanofluid. It is estimated that by replacing conventional coolant with this nanofluid, reduction in the frontal area of radiator is done which gives more flexibility for industrial design, more eco-friendly vehicle which produces less drag and hence less the fuel cost.

Heat transfer enhancement of hybrid nanofluids over porous cone

Abstract The nanofluid is most advantageous to enhance the heat efficiency of base fluid by submerging solid nanoparticles in it. The metals, oxides, and carbides are helpful to improve the heat transfer rate. In the present analysis, the role of the slip phenomenon in the radiative flow of hybrid nanoliquid containing SiO2 silicon dioxide and CNTs over in the porous cone is scrutinized. The behavior of the magnetic field, thermal conductivity, and thermal radiation are examined. Here the base fluid ethylene glycol water (C2H6O2−H2O) is used. Accepting similarity transformation converts the controlling partial differential equations (PDEs) into ordinary differential equations (ODEs). The numerical solution is obtained by utilizing the Lobatto-IIIa method. The significant physical flow parameters are discussed by utilizing tables and graphs. Final remarks are demonstrating the velocity profile is declined via higher magnetic parameter while boosted up for nanoparticles volume fraction. Furthermore, the thermal profile is enriching via thermal conductivity parameter, radiation parameter, and nanoparticles volume fraction.