Glycol Solution Research Articles

Water retention and heat storage characteristics of phase change hydrogel in cooling pavement

Phase change hydrogel (PCH) combines the heat storage characteristics of phase change material with the water retention capacity of hydrogel, showing great potential in cooling pavement applications. This study aims to investigate the water retention and heat storage properties of PCH in cooling pavement, providing new insights for mitigating the urban heat island effect. Based on the principle of osmotic pressure, polyethylene glycol (PEG) solution was actively absorbed by superabsorbent polymers (SAP) to form stable PCH. By infusing the asphalt mixture skeleton with PCH-containing phase change grouting material (PCGM), a temperature-regulating phase change grouting pavement (PCGP) can be obtained. Morphological characterization showed that PCH was uniformly distributed in PCGM and effectively locked PEG during high temperature and water absorption/release processes without leakage. PCH imparted excellent water retention properties to PCGM, with a saturation water absorption rate of 44.1 %, which is 6.2 times higher than the control group, and a water retention rate of 34.31 % after heating at 60 °C for 12 hours. Furthermore, PCGM exhibited considerable heat storage performance, with a melting enthalpy of 15.74 J/g and a crystallization enthalpy of 12.07 J/g. Based on these, PCGP demonstrated outstanding temperature-regulating ability, reducing surface temperatures by 9.3 °C and 11.6 °C under dry and saturated conditions, respectively, compared to control pavement. In conclusion, this study provides a theoretical basis for the development of novel cooling pavement materials and shows great potential for its wide application in urban infrastructure construction.

Effect of Halide Anions on Electrochemical CO2 Reduction in Non-Aqueous Choline Solutions using Ag and Au Electrodes.

In this study, the effect of halide anions on the selectivity of the CO2 reduction reaction to CO was investigated in choline-based ethylene glycol solutions containing different halides (ChCl : EG, ChBr : EG, ChI : EG). The CO2RR was studied using silver (Ag) and gold (Au) electrodes in a compact H-cell. Our findings reveal that chloride effectively suppresses the hydrogen evolution reaction and enhances the selectivity of carbon monoxide production on both Ag and Au electrodes, with relatively high selectivity values of 84 % and 62 %, respectively. Additionally, the effect of varying ethylene glycol content in the choline chloride-containing electrolyte (ChCl : EG 1 : X, X=2, 3, 4) was investigated to improve the current density during CO2RR on the Ag electrode. We observed that a mole ratio of 1 : 4 exhibited the highest current density with a comparable faradaic efficiency toward CO. Notably, an evident surface reconstruction process took place on the Ag surface in the presence of Cl- ions, whereas on Au, this phenomenon was less pronounced. Overall, this study provides new insights into anion-induced surface restructuring of Ag and Au electrodes during CO2RR, and its consequences on the reduction performance on such surfaces in non-aqueous electrolytes.

Rapid Detection of Ultralow H2S Concentration with on-chip Fabrication of SnO2-based Gas Sensors by Direct Electrodeposition from Non-Aqueous Solvents

Hydrogen sulfide (H2S) causes significant impacts on human health and the environment due to its highly toxic properties. Thus, the design and development of gas sensors to detect and monitor H2S (especially at extremely low concentrations) are challenging tasks for scientists. In this work, SnO2 gas sensors were successfully synthesized directly on a chip by Sn electrodeposition from ethylene glycol solutions + a post-treatment (calcination) stage (to form and stabilize SnO2). Mechanisms and kinetics of Sn electrodeposition on Pt microelectrodes were thoroughly studied using electrochemical techniques. These fabricated gas sensors exhibit a high selectivity toward H2S gas and an effective response to low-level concentrations of H2S in the range of 0.1 ppm–1 ppm at different working temperatures. The influence of electrodeposition conditions and calcination temperatures on the gas response of sensors were also examined. The results have verified that the electrodeposition method from ethylene glycol solutions is promising for the fabrication of ultrasensitive on-chip gas sensors.

Thermal analysis of metal foam and nanofluid integration in an asymmetrical heated channel

The flow and heat transport presentation of the nanofluid flowing through the metal foam (MF) positioned inside the asymmetrical heated horizontal channel is evaluated computationally in the current study. The MF of 20 pores per inch (PPI) with porosity 0.918 is inserted into horizontal channel test section. The test segment is heated from the top wall with the help of plate (aluminum) heater assemblage positioned at the top of the channel. The novelty of the current examination is to extract the consequences of nanofluids such as Al2O3-H2O and CuO-H2O flowing through the MF filled test segment at various velocities ranging from 0.02 to 0.15 m/s. The conjugate heat transport examination is executed through MF region using integrated DEF (Darcy Extended Forchheimer) with LTE (local thermal equilibrium models). The improvement in thermal presentation achieved for nanofluids are likened with H2O and H2O-C2H6O2 (water with 50 % ethylene glycol) solution and also with clear channel. The procedure adopted in the current analysis is initially confirmed with the help of comparison of present work result with literature upshots. The outcomes are presented in terms of friction factor (FF), Nusselt number (Nu), Colburn j factor, performance evaluation criteria (PEC) and pumping power (PP). The CuO-H2O nanofluid showed the best performance (average PEC of 1.4) among all the fluids considered in the present examination.

Low temperature resistant flexible zinc-ion hybrid supercapacitor

Zinc-ion hybrid supercapacitors (ZIHS) have high capacity and power density, as well as safety and stability. However, ZIHS are susceptible to electrolyte solidification and deactivation under low temperatures, resulting in rapid capacity degradation. Consequently, their practical use in cold environments is limited. In this study, solid organic hydrogels were prepared as electrolytes using ZnCl2 in a solution of ethylene glycol (EG) and deionized water (H2O), incorporating polyvinyl alcohol (PVA). The hydrogen bonding between PVA and EG effectively suppresses ice crystal formation and promotes the growth of PVA crystal domains. In addition, EG can also form hydrogen bonds with H2O molecules, further preventing H2O crystallization, thereby improving the low temperature resistance of the ZIHS. The results show that the specific capacitance of ZIHS prepared with MnO2 as cathode electrode material and active carbon (AC) as anode electrode material can reach 60 mF cm−2 at −30 °C, and the capacity retention rate can reach 81.2 % after 8000 cycles. In addition, it was found that ZIHS still had good stability after bending at different angles at −30 °C. The development of ZIHS with excellent flexibility and low-temperature resistance is crucial for advancing electronics capable of operating in cold environments.

Numerical investigation on thermal management performance of soft packing Li-ion batteries with oblique multi-channel cold plates

During the driving process of electric vehicles (EVs), the continuous high-rate discharge of the power battery causes significant heat accumulation. An efficient battery thermal management system (BTMS) is critical for the safe and stable operation of EVs. In this study, an oblique channel cold plate (OCCP) is designed based on the traditional straight channel cold plate (SCCP) in order to addresses the problem of excessive and uneven temperatures during the high-rate discharge of soft packing lithium-ion batteries. Effects of glycol solution concentration, coolant mass flow rate, coolant inlet temperature, oblique angle for cooling channel, ambient temperature and discharge rate for the cell on the performance characteristics of BTMS, including the cooling efficiency (φ) and pressure drop (ΔP), are analyzed numerically with Ansys Fluent software. The results show that the OCCP has better cooling performance and lower pressure loss than the SCCP. Based on the analysis with the orthogonal design method, when the glycol solution concentration is 20 %, the mass flow rate is 1.0 g/s, and the inlet temperature is 25 °C, the BTMS with SCCP could obtain the optimal performance, corresponding to that the maximum temperature (Tmax) of the battery is controlled at 32.056 °C, while the φ is 0.581, and the ΔP across the cold plate is 52.652 Pa. Furthermore, the cooling efficiency φ of the cold plate decreases with the increase in the oblique angle. When the ambient temperature is 35 °C, the OCCP with a 20° oblique angle provides the best cooling effect for the battery during a 10C discharge. This work is helpful for the design of liquid cold plates in BTMS under high-rate discharge conditions for power battery of EVs.

Electropolishing of Magnesium and Its Alloys using a Safe Glycol Solution containing Sodium Chloride

Abstract The electropolishing behavior of pure magnesium and its alloys in ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TrEG), and tetraethylene glycol (TeEG) solutions containing sodium chloride was investigated using electrochemical measurements, microscopic observations, and reflectance measurements. Large light-grayish cloudy areas with micrometer-scale linear irregularities were formed on the magnesium surface via constant-voltage electrolysis in the EG solution, whereas mirror-finished magnesium surfaces were successfully obtained in the DEG and TeEG solutions. Among these, the DEG solution is considered appropriate for electropolishing because of its lower viscosity and market price. The reflectance of the entire visible wavelength region gradually increased with time during electrolysis in the DEG solution at 308 K. We found that short-term electrolysis for 3 min at the higher voltage of 75 V should be selected if a moderately polished surface is to be rapidly obtained, whereas long-term electrolysis for 60-300 min at 50 V should be performed if a highly polished surface with an extremely high reflectivity measuring more than 80% can be obtained. Three-dimensional magnesium specimens with curved and spiral shapes and an LZ91 magnesium alloy consisting of a simple solid-solution matrix can also be electropolished via electrolysis in a DEG solution.

A clean transfer approach to prepare centimetre-scale black phosphorus crystalline multilayers on silicon substrates for field-effect transistors

Recently reported direct growth of highly crystalline centimetre-sized black phosphorus (BP) thin films on mica substrates by pulsed laser deposition (PLD) has attracted considerable research interest. However, an effective and general transfer method to incorporate them into (opto-)electronic devices is still missing. Here, we show a wet transfer method utilizing ethylene-vinyl acetate (EVA) and an ethylene glycol (EG) solution to transfer high-crystalline large-area PLD-BP films onto SiO2/Si substrates. The transferred films were used to fabricate BP-based bottom-gate field-effect transistor (FET) arrays exhibiting good uniformity and continuity, with carrier mobility and current switching ratios comparable to those obtained in as-grown BP films on mica substrates. Our work presents a promising transfer strategy for scalable integration of on-substrate grown 2D BP into devices with more complex structures and further investigation of material properties.

Charge Transfer Mechanisms of Adaptive Multicomponent Solutions at Solid-Liquid Interfaces for Real-Time Coolant State Monitoring.

Charge-transfer mechanisms in adaptive multicomponent solutions at liquid-solid interfaces with triboelectric probes are crucial for understanding chemistry dynamics. However, liquid-solid charge transfer becomes unpredictable, due to the components or interactions in solutions, restricting its potential application for precise monitoring of liquid environments. This study utilizes triboelectric probes to investigate the charge transfer of chemicals, applying this approach to real-time coolant state monitoring. Analysis of electrical signal dynamics induced by ethylene glycol and its oxidation byproduct, oxalic acid, in ethylene glycol solutions reveals that hydrogen bond and ion adsorption diminishes the efficiency of electron transfer at the liquid-solid interface. These findings promote the engineering of the triboelectric probe that enhances coolant quality with remarkable sensitivity (detection limit: 0.0001%) and a broad freezing point operational range (0 to -49 °C). This work advances the precise control of the charge dynamics and demonstrates the potential of triboelectric probes for interdisciplinary applications.

Structural and dynamic behaviour of concentrated aqueous solutions of (poly)ethylene glycols: Insight into the impact of hydrophobicity, hydrogen bonding and chain length

Understanding the delicate interplay between hydrophobicity/hydrophilicity, hydrogen bonding ability and solute size in modulating the chemico-physical properties of aqueous solutions with increasing solute concentration is a challenging task. Here, we focus on how bulk properties, such as diffusion and aggregation behaviour, are affected by the different hydration patterns observed for differently concentrated aqueous solutions of (poly)ethylene glycols, and their corresponding methoxyethers, of various lengths. Using a combined experimental and computational approach, we analyse solutions of ethylene glycol (EG), dimethoxyethane (DME), polyethylene glycol with 4 repeating units capped with either hydroxyl (PEG200) or methoxyl (PEG250DME) tails, and polyethylene glycol with 9 repeating units (PEG400). By disentangling the contributions of hydrophobicity, hydrogen bonding ability, and chain length, we observe that for the smaller solutes electristriction and hydrophobic hydration are the main phenomena occurring. Instead, as the solute becomes larger, these effects give way to the non-trivial conformational flexibility that can either favour or disfavour intermolecular interactions which lead to the formation of water-rich regions excluded from the solute.

Sn nucleation and growth from Sn(II) dissolved in ethylene glycol: Electrochemical behavior and temperature effect

Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied. Typical reduction and oxidation peaks observed in voltammograms have demonstrated the capability of ethylene glycol solutions to electrodeposit Sn. The temperature-dependence of diffusion coefficient values derived from potentiodynamic and potentiostatic studies helped to determine and validate estimations of the activation energy for Sn(II) bulk diffusion. Chronoamperometric results have identified that, the suitable model to describe the early stage of Sn electrodeposition could be composed of Sn three-dimensional nucleation and diffusion-controlled growth and water reduction contributions, which was duly validated by theoretical and experimental approaches. From the model, typical kinetic parameters such as the nucleation frequency of Sn (A), number density of Sn nuclei (N0), and diffusion coefficient of Sn(II) ions (D), were determined. The presence of Sn nuclei with excellent quality and their structures were verified using SEM, EDX, and XRD techniques.

Pilot randomized trial of efficacy and safety of yogic technique versus polyethylene glycol solution for bowel preparation in colonoscopy

Pilot randomized trial of efficacy and safety of yogic technique versus polyethylene glycol solution for bowel preparation in colonoscopy

Characterization of Iron Oxide Nanotubes Obtained by Anodic Oxidation for Biomedical Applications-In Vitro Studies.

To improve the biocompatibility and bioactivity of biodegradable iron-based materials, nanostructured surfaces formed by metal oxides offer a promising strategy for surface functionalization. To explore this potential, iron oxide nanotubes were synthesized on pure iron (Fe) using an anodic oxidation process (50 V-30 min, using an ethylene glycol solution containing 0.3% NH4F and 3% H2O, at a speed of 100 rpm). A nanotube layer composed mainly of α-Fe2O3 with diameters between 60 and 70 nm was obtained. The effect of the Fe-oxide nanotube layer on cell viability and morphology was evaluated by in vitro studies using a human osteosarcoma cell line (SaOs-2 cells). The results showed that the presence of this layer did not harm the viability or morphology of the cells. Furthermore, cells cultured on anodized surfaces showed higher metabolic activity than those on non-anodized surfaces. This research suggests that growing a layer of Fe oxide nanotubes on pure Fe is a promising method for functionalizing and improving the cytocompatibility of iron substrates. This opens up new opportunities for biomedical applications, including the development of cardiovascular stents or osteosynthesis implants.

Effect of Changing the Concentration of Zinc Oxide Nanoparticles on the Viscosity of the Polyacrylamide / Polyethylene Glycol Solutions

In this work, Polyacrylamide/ Polyethylene glycol solutions of different molecular weights for Polyethylene glycol and different concentrations (17, 29, 38, 45, and 57 %) of ZnO nanoparticles were prepared by dissolving 0.5g of Polyethylene glycol in 20mL Polyacrylamide, then adding different concentrations of ZnO nanoparticles. Relative viscosity values are calculated by using the efflux time of the solutions, the viscosities(relative viscosity (ƞr), specific viscosity (ƞsp), reduced viscosity (ƞred) and inherent viscosity (ƞint) were calculated for all solutions, where measurements indicated an increase in these properties with increased concentration of ZnO nanoparticles and increased molecular weight of Polyethylene glycol. Viscosity is a significant parameter during the electrospinning process, and if the molecular weight increases, the viscosity of the solutions increases, making subsequent synthesis and purification more difficult. the constants KH and KK were calculated from the slopes of the viscosity values related to the Huggins and Kramer equations. These results can be used in many applications and scientific studies.

Enhancing the PEEK composites-titanium interface performances through electrochemical treatment in fibre-metal laminates for aerospace applications

In this work, different surface treatments were investigated to improve the adhesion between grade 5 titanium alloy and carbon fibre-reinforced PEEK composites for aerospace applications. Three types of processes were compared: mechanical treatment (MT), carried out by sander with #80 grit sandpaper, chemical treatment, using a silane coupling agent (SIL) and electrochemical treatment, performed by anodic oxidation. The latter was performed by using an ethylene glycol solution composed of 0.5%wt of ammonium fluoride (NH4F) and variable volume content of deionized water: 5%v/v, 20 % v/v, 50 % v/v. The ammonium fluoride content was fixed, while the ethylene glycol percentage depend on the variation of water volume. Two values of electric potential were evaluated: 30V and 50V. Finally, for each potential and water content, three different anodizing times were studied: 10 min, 30 min, and 60 min. Morphology studies were performed through Scanning electron microscopy to evaluate how the anodizing parameters could affect the shape of the nanotubes (NTs) layers. Moreover, short beam shear tests were carried out to evaluate the achieved improvement given by the different surface treatments.

Synthesis of Silver Nitrate by Evaporation Chemical Reduction Process as Potential Materials for Silver Nanowires Application

In this study, we conducted the extraction of silver nitrate (AgNO3) using the chemical reduction evaporation method, involving silver metal (Ag) with a molarity of 7.716 M and nitric acid (HNO3). The heating process via evaporation was carried out at 85oC for 2 hours. Subsequently, the synthesis of silver nanowires (AgNWs) was performed using a 0.3 M of AgNO3 solution in ethylene glycol (EG), polyvinyl pyrrolidone (PVP), and Iron (III) Chloride hexahydrate (FeCl36H2O). XRD analysis of the AgNO3 sample revealed an orthorhombic crystal structure with a single AgNO3 phase peak. In AgNWs, three crystalline phases were observed, with the Ag phase being the most dominant. The average crystal size of AgNO3 and AgNWs was 109.42 nm and 22.06 nm, respectively. The average crystal size of the AgNO3 sample may be influenced by the aggregation between crystal nuclei during the heating process. XRF analysis indicated a 98.84% Ag concentration in AgNO3. SEM-EDS analysis showed that the AgNO3 sample had a non-aggregated morphological structure, with particle size measuring 49.46 μm and an overall AgNO3 purity of 92.68%. The SEM image of the AgNWs sample displayed a very homogeneous diameter of ∼200 nm with a length of around 10-20 μm. Meanwhile, AgNWs exhibited a morphology resembling rod-shaped wires with a purity of 68% for Ag.

Anodic Production and Characterization of Biomimetic Oxide Layers on Grade 4 Titanium for Medical Applications.

Biomaterials are the basis for the development of medicine because they allow safe contact with a living organism. The aim of this work was to produce innovative oxide layers with a microporous structure on the surface of commercially pure titanium Grade 4 (CpTi G4) and to characterize their properties as drug carriers. The anodization of the CpTi G4 subjected to mechanical grinding and electrochemical polishing was carried out in a solution of 1M ethylene glycol with the addition of 40 g of ammonium fluoride at a voltage of 20 V for 2, 18, 24, and 48 h at room temperature. It was found that the longer the anodization time, the greater the number of pores formed on the CpTi G4 surface as revealed using the FE-SEM method, and the greater the surface roughness determined in profilometric tests. As the anodizing time increases, the amount of the drug in the form of gentamicin sulfate incorporated into the resulting pores decreases. The most favorable drug release kinetics profile determined via UV-VIS absorption spectroscopy was found for the CpTi G4 anodized for 2 h.

Experimental study on the preparation of superalloy Inconel718 heat exchanger channels by electrochemical etching method

The nuclear energy field requires the construction of heat exchangers that can withstand sufficiently high temperatures. In this paper, the etching technique was utilized to fabricate heat exchange channels on Inconel718 plates, and experiments were carried out in NaCl-ethylene glycol solution, three temperature conditions of 35 °C, 40 °C, and 45 °C, and two concentrations of electrolyte solutions, 0.5 mol/L and 1 mol/L, with the addition of 50 kHz ultrasound for comparison. The experimental results show that the etching rate can be as high as 2.894 mm/h, and the inter-electrode current is as high as 908 mA. The roughness characterization of the etching channel Ra and Rq measured by the aspheric surface measuring instrument can be as low as 2.416 μm and 2.647 μm, respectively. In the images generated by SEM scanning, it is found that uneven distribution of pits and bumps exist in the etching channel, but their diameters are all less than 0.1 μm, which means the etched channel is acceptably smooth.

Broad-band absorption and photo-thermal conversion characteristics of rGO-Ag hybrid nanofluids

In the current paper, the thermo-physical, optical and photo-thermal conversion characteristics of reduced graphene oxide nanosheets and silver nanoparticles suspended in water and water + ethylene glycol solution (1:1) were experimental investigated under indoor conditions. The results indicated that the hybrid nanofluids have a good solar absorption in both visible and near-infrared regions (220–1400 nm). Comparing transmission spectra and extinction coefficients of rGO-Ag/water and rGO-Ag/W + EG hybrid nanofluids it is found that the use of rGO-Ag/W + EG hybrid nanofluid is much more beneficial than the rGO-Ag/water nanofluid in solar applications. The rGO-Ag /water and rGO-Ag /W + EG hybrid nanofluids with 0.10 wt% exhibit a relative increase in the temperature difference by about 21 % and 37 % compared to the base fluids and also stored energy values of 4989 J and 5432 J respectively, after an irradiation time of 60 min. This study emphasized the solar potential of rGO-Ag hybrid nanofluids for improving the direct absorption solar collectors performance.

Reversible phase transformations between Pb nanocrystals and a viscous liquid-like phase.

Phase transformations have been a prominent topic of study for both fundamental and applied science. Solid-liquid reaction-induced phase transformations can be hard to characterize, and the transformation mechanisms are often not fully understood. Here, we report reversible phase transformations between a metal (Pb) nanocrystal and a viscous liquid-like phase unveiled by in situ liquid cell transmission electron microscopy. The reversible phase transformations are obtained by modulating the electron current density (between 1000 and 3000 electrons Å-2 s-1). The metal-organic viscous liquid-like phase exhibits short-range ordering with a preferred Pb-Pb distance of 0.5 nm. Assisted by density functional theory and molecular dynamics calculations, we show that the viscous liquid-like phase results from the reactions of Pb with the CH3O fragments from the triethylene glycol solution under electron beam irradiation. Such reversible phase transformations may find broad implementations.