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Summary In wellbore drilling, it is appreciable to devise methods to study the rheology of high-speed annulus fluid flows. In this paper, a high-speed Taylor-Couette system (TCS) was devised to explore non-Newtonian fluid flow behavior appraised by SiO2 nanoparticles toward friction reduction, power saving, and rheology modeling of nanofluids. Water-based mud (WBM) as an environmentally friendly drilling fluid is investigated by adding SiO2 nanoparticles at four low-volume concentrations of 0.05, 0.1, 0.5, and 1% at speeds from 0 to 1,600 rev/min with 200 rev/min intervals in the TCS. Five rheology models based on the Herschel-Bulkley-Extended (HBE) model and a generalized Reynolds number were optimized to fit with the experimental data. All models except the Newtonian model have fitted all nanofluids with high accuracy, especially Bingham and HBE models. Negative deviation from Darcy friction was avoided for power-law (PL) and Herschel-Bulkley (HB) models using the modification to the generalized Reynolds number. Higher energy saving and enhanced rheology is reported particularly at lower volume concentrations of SiO2 WBM nanofluids. The Darcy friction factor deviated from laminar flow at the generalized Reynolds number beyond 2,000 into turbulent, which is a good indicator for the flow condition of complex non-Newtonian nanofluids in real-life application.

The purpose of this study was to evaluate the controlled-release properties of nutrients from coconut water-based hydrogel. Hydrogels were prepared at varying proportions of gellan and xanthan gums such that the total weight of the gelling agents for all 11 formulations was 1% (w/w) in coconut water. The formulation of the hydrogel was selected using gravimetric analysis by evaluating the dissolution weight of the hydrogel in simulated gastric fluid and simulated intestinal fluid. Interestingly, hydrogel with 0.7% gellan gum and 0.3% xanthan gum showed the most tolerance towards simulated gastric and intestinal fluids over a 1-h period. The in-vitro release study was performed in simulated gastric fluid and followed by simulated intestinal fluid for about 2 h. The trend of release profile showed that the hydrogel had the ability to sustain the nutrients release over a period of 1 h. After 75 min, the release trend was static indicated the nutrients was released from the hydrogel. In conclusion, a coconut water-based hydrogel formulated with 0.7% of gellan and 0.3% of xanthan gum has demonstrated its controlled-release property as evidenced by its effectiveness in the sustained release of nutrients over a period of 1 h.

Due to its low toxicity and because they are environmentally friendly, water-based paints are the most employed in the world, mainly to coat buildings. In these systems, the water evaporation process is important to determine the final paint quality and should be carefully evaluated. This work evaluated the suitability of Crank’s model, solution of the Fick’s second law, to experimental drying data of water-based architectural paints to better understand this process. Therefore, the data were adjusted to the linearized and original model and the number of terms used in its approximation was varied. For each model, the diffusion coefficient of the water in the coating material and the coefficient of determination were calculated. The results showed that the use of the linearized model is not adequate to determine the diffusion coefficient, but the nonlinear adjustment of the original model can adjust the data for some paints. These results also suggest the addition of terms to the sum of the model to improve its quality in the initial stages of drying. DOI: http://dx.doi.org/10.17807/orbital.v13i1.1508

In this study, micron-sized flake shaped carbonyl iron (CI) water-based MR fluids were prepared with adding laponite and oleic acid as an additive and surfactant, respectively. The MR suspensions are comprised of the fixed CI particles and water weight %, while weight % of laponite and oleic acid changes from 1 to 3 wt% and 0.5 to 1.5 wt%, respectively. The remarkable enhancement in magnetorheological properties was obtained with improved sedimentation stability for CI/water MR suspensions with the addition of laponite and oleic acid. It was found that at the lowest magnetic field strength, the higher laponite concentration is effective, while at the highest magnetic field strength, the smaller concentration was effective. It was because of the combined effect of the field-induced CI chains and the laponite clay gel network. Its storage moduli showed a stable plateau area for whole angular frequencies, suggesting distinguished solid-like behavior of the MR fluid. Finally, a novel correlation was obtained between the initial settling rate of the CI particles and magnetorheological behavior of CI/laponite/OA MR suspensions with 1 wt% laponite and 0.5 wt% oleic acid, which has less zero-field, high on-state shear stress with enhanced sedimentation stability. The prepared MR fluids are a reliable industrial application vibration-isolation, clutch, and brake.

Water-based lubricant is regarded as an important substitute for the oil-based lubricant when used in improving the tribological properties. Additives are urgent required in water-based lubricants as their disadvantages of poor lubricating properties. In the present work, a new additive containing S, P, Cl active element was synthesized, and the tribological properties were evaluated by using a four-ball tester. The impact of temperature on the tribological properties of water-soluble lubricant was also studied. The worn surfaces were analyzed by X-ray absorption near-edge structure (XANES) spectroscopy. The results show that the synthesized additive exhibit better tribological properties than oleate solution at higher load. XANES spectroscopy indicates that the compositions of tribofilms changed with the temperature. The different composition of the tribofilm has a great influence on tribological behavior.

This study reports a simple approach to prepare a nano-TiO2-Sb-Ni yellow ink-jet ink. Yellow pigments, in terms of their morphology and color appearance, were synthesized by changing Ni/Sb molar ratios and calcination temperatures. Moreover, the particle size of optimal nano-TiO2-Sb-Ni pigment controlled by CTAB and PVP in a co-precipitation process. TGA, spectrophotometry, and XRD were used to characterize the prepared nano-TiO2-Sb-Ni pigments. SEM and TEM were used to investigate the morphology and size of the prepared nano-pigments, respectively. Finally, the synthesized spherical nano-pigment had an average diameter of 65 nm was well dispersed in water. A general ink-jet printer printed the stable, homogenous nano-ceramic ink. Ultimately, the more yellow appearance could be obtained through increasing the number of printing runs.

While drilling a well, drilling fluids incurs 15–18 per cent of the overall cost. While preparing a drilling fluid, there are three fundamental considerations. It should be simple to use, not too expensive, and it should be environmentally sustainable. The formulation of a mud system begins with the selection of a mud family that, according to the rock formations and drilling fluid properties, will be sufficient for drilling a well. In order to develop a drilling fluid, we experimented and used tamarind seed powder with bentonite and barite. With approximately 8 to 10 seeds in each pod, tamarind seeds contained in kernels or pods are around 3 to 6 in. long. The average weight of pod is around 0.064 g. In general, a complete grown tamarind tree produces around 175 to 250 kg of seed/kernel. The density of different samples with a mixture of bentonite, barite and tamarind seed powder ranging from 5 to 20 g was found using mud balance. Results show that average mud density received after five test runs of the experiment was 8.662 ppg which is good to be considered as a good drilling fluid.

This investigation is based on the fabrication and characterization of nano-biocomposites made from natural resources like jute and soy seeds along with glutaraldehyde as curing agent. Water based soy resin was modified with different weight percentages of natural and organically modified nanoclay and applied as matrix along with jute to prepare the nanocomposites. Composites were degraded under soil burial condition and lost 60–75% of their original weight after 60 days. These composites were characterized from various aspects like thermal stability, mechanical testing and fire retardancy to ensure them to be used for end application like furniture, and automobile interiors.

A new metal–organic framework (MOF) compound [Mn2(2,2′-bca)2(H2O)2]n (Mn-MOFs) was successfully synthesized by solvothermal method, and Mn-MOFs@Zn material was prepared by loading zinc phosphate onto Mn-MOFs by ball milling, then Mn-MOFs@Zn was added to the water-based acrylic paint to prepare Mn-MOFs@Zn@acrylic coating. The AC impedance test results showed Mn-MOFs@Zn@acrylic coating has higher corrosion inhibition performance and stability to mild steel when compared with blank coating. The impedance modulus of the blank coating in the low frequency region decreased by 90%, and the Rct showed a trend of first increasing and then decreasing over time, the maximum Rct was only 303.8 Ω, which was only Mn-MOFs@Zn@acrylic coating one-seventh of the Rct value. The artificial scratch experiment showed that the Mn-MOFs@Zn@acrylic coating only slightly corrodes at the scratches, because Mn-MOFs@Zn material made the coating a self-repairing function and improved the durable anticorrosion performance of the acrylic coating.

A systematic approach was used to investigate the weathering-induced degradation of a common water–based intumescent coating. In this study, the coatings are intended for humid indoor applications on steel substrates. The coating contains ammonium polyphosphate, pentaerythritol, melamine, and polyvinyl acetate. By replacing each ingredient with a less water-soluble substance, the most vulnerable substances, polyvinyl acetate and pentaerythritol, were identified. Furthermore, the weathering resistance of the system was improved by exchanging the ingredients. The coatings were stressed by artificial weathering tests and evaluated by fire tests. Thermogravimetry and Fourier-transform infrared spectroscopy were used to study the thermal decomposition. This study lays the foundation for the development of a new generation of water-based intumescent coatings.

The proper selection of drilling fluids formulations and its treatment has always been a challenge and requires a great effort to ensure optimum drilling performance. The objective of this paper is to assist the mud engineer in selecting the water-based drilling fluid formulations that are best suited for a certain application. To achieve this target, the field practices were combined with the literature to study the most practiced water-based drilling fluid recipes used for onshore gas applications in the Middle East (i.e., spud mud, high-bentonite spud mud, salt/polymer mud, and high-overbalanced mud). From both field practices and deep literature review, it is recommended that both spud mud and high-bentonite spud mud be prepared and pre-hydrated for 4–6 h before a well spud. Also, it is important to add detergents with high-viscosity sweeps to avoid the bit balling and maintain the gel strength. While for salt/polymer mud, the regular addition of sodium sulfite is necessary for polymers stabilization, and the efficient solids control equipment performance is essential. To avoid the solids sagging issues associated with drilling high-pressure high-temperature deep gas reservoirs, it is recommended to either uses sag resistance materials, micronized weighting materials, or a combination of different weighting materials. The high-overbalanced mud is the most effective and efficient type when drilling a combination of natural fractured depleted gas reservoirs with high-pressure gas reservoirs.

A green synthetic route to the facile one-pot multicomponent synthesis of pyrano[2,3‐d]pyrimidines and pyrido[2,3‐d]pyrimidines have been developed using magnetized deionized water (MDW) as a green solvent under catalyst-free conditions. All reactions carried out in a short period of time and the products are obtained in high-to-excellent yields. The developed synthetic technique offers numerous advantages including eco-friendly, clean synthesis, simplicity, low cost, short reaction times, high reaction yields, and easy workup compared to the traditional synthetic method. Moreover, the reaction rates were followed spectrophotometrically by monitoring the changes in the absorption spectrum of the reaction mixture in ordinary deionized water and MDW.

Plastic waste is one of the biggest growing factors contributing to environmental pollution. So far there has been no established method to detect and identify plastics in environmental matrices. Thus, a method based on their characteristic fluorescence behavior is used to investigate whether plastics can be detected and identified in tap water under laboratory conditions. The experiments show that the identification of plastics as a function of water depth is possible. As the identification becomes more difficult with higher water depths, investigations with a highly sensitive imaging method were carried out to obtain an areal integration of the fluorescent light and thus better results.

This study synthesized water-based polyurethane with acrylate terminal group (WPUA) using the long carbon chain of stearyl acrylate to synthesize hydrophobic poly-stearyl acrylate (PSA). The proposed process could minimize environmental pollution caused by fluorine-containing monomers. As a water-based polyurethane (WPU) end-capping agent, the hydrophobic PSA and the hydrophilic and water vapor permeable WPU are copolymerized to form a WPUA functional resin with simultaneous water vapor permeability (WVP) and water repellency. Here, 2-mercaptoethanol was used to control the molecular weight of PSA to prepare the acrylate end-capping agent. PSA was then employed in WPU to form WPUA, which is characterized by the moisture permeability of WPU and water repellency of acrylic resin simultaneously. During the WPUA process, dimethylacetamide was used as a neutralizer to replace the traditional toxic chemical control drug triethylamine. This study set up the material and chemical structure to replace the toxic chemical-controlled drugs and organofluoride in the traditional preparation of moisture permeable and water repellent materials. The proposed process was proven to reduce the consumption of organic solvent, achieve WPUA copolymer stability, and provided moisture permeable and water repellent functions. In addition, Fourier transform infrared spectroscopy was used to determine the structure of WPUA, while thermogravimetry analysis and differential scanning calorimetry were performed to establish the thermal properties of WPUA. After the WPUA was padded on nylon fabric, its water drop contact angle was observed through a scanning electron microscope. The results showed that the contact angle of nylon fabric increased significantly, water repellency was reached, and WVP rises by 23.75%.

The need for an environmentally friendly tool in textile production is the major concern of consumers and traders. The current study is aimed to use supercritical CO2 technology to improve dyeing o...

Thermoresponsive nonionic block copolymers, methoxy poly(ethylene glycol)-b-poly(N-isopropylacrylamide) (MPEG-b-PNIPAM), were investigated as chemical aids for the water-based oil sands extraction ...

The energy industry is exploring sustainable chemistry and engineering solutions for exploitation of shale reservoirs. Smectite-rich shale is challenging to drill with traditional water-based drill...

International audience; This study reports an optimization of the extraction of sinapine from industrial mustard bran using an ethanol/water mixture as a green solvent. Response Surface Methodology was used to determine the optimal operating conditions for the extraction process. The results show that to obtain a maximum yield of sinapine, the extraction process must be carried out at 75 °C with 70% ethanol and a ratio of 10 mL/gBDM. Under these conditions, the extraction kinetics have shown that equilibrium is reached for a concentration of 8.8 ± 0.1 mg/gBDM in 30 min. The mustard bran is exhausted to 95% sinapine after two successive extractions. The selectivity of the extraction process for sinapine could be increased by 20% using an ethanol concentration of 83%, the yield of sinapine is then 8.0 ± 0.1 mg/gBDM.

Nanocellulose fibers (NCF) is a renewable biodegradable polymer in nature. It has extensively interest as a reinforcement material in nanocomposites due to its nanoscale advantages. However, the efficiency of NCF dispersion in polymer matrix has limitation due to its self-agglomeration.The objective of this research was to prepare surface-modified NCF using three different acids; succinic anhydride, phthalic anhydride and citric acid. The molar ratios of acid to anhydroglucose units in NCF used in this work were 6:1, 8:1 and 10:1. The effects of acid types and molar ratios toward physical properties were studied. The results showed that succinic anhydride-modified NCF provided the highest DS range from 0.46-0.86. Dispersion of succinic anhydride-modified NCF provided good stability in water for 30 days. The succinic anhydride-modified NCF of 1:6 molar ratio is suitable for emulsion coating application.

A new scandium naphthalenedicarboxylate with the framework composition [Sc-2(1,4-NDC)(3)] (H-2-1,4-NDC = 1,4-naphthalenedicarboxylic acid) was obtained under hydrothermal synthesis conditions. A st ...

In this paper, a water based All Dielectric Frequency Selective Surface (ADFSS) is presented made of renewable materials. This surface is based on a modified dielectric resonator incorporating air ...

Although metal-organic frameworks (MOFs) show numerous advantages over other crystalline materials, their industrial relevances have been impeded owing to their many drawbacks such as environmental impacts and economic costs of their synthesis. A green preparation pathway could greatly reduce the environmental costs, energy, and the need for toxic organic solvents, and consequently reduce the production cost. Thus, the most desirable synthesis route is the replacement of harsh organic solvents with aqueous solutions to abate environmental and economic impacts. This review summarizes recent research advancements of water-based routes for MOF synthesis and gives a brief outline of the most prominent examples. The challenges and prospects of the commercialization of promising MOFs in the future are also presented. This study aims to offer necessary information regarding the green, sustainable, and industrially acceptable fabrication of MOFs for their commercial applications in the future.

Two novel methods for spectrophotometric determination of Cu2+ ion using synthesized and characterized furfuraldehyde fluorescein diacetate hydrazone (FFDH) and furfuraldehyde fluorescein hydrazone (FFH) have been proposed. Addition of Cu2+ to FFDH and FFH solutions results in a rapid color change from colorless to dark yellow. Experimental results show that FFH and FFDH both can provide a rapid, selective and sensitive response to Cu2+ within a linear dynamic range of 7–33 µM and the detection limits of 1.1 × 10–7 and 7 × 10–8 M, respectively. Apparently, the detection limit of FFDH is lower than that of FFH, which indicates that FFDH forms a more stable complex with Cu2+. In addition, the detection of Cu2+ in water samples was also studied; as a result, the developed FFDH was found to be more applicable than FFH for spectrophotometric determination of Cu2+ in environmental water samples. Particularly, as a lipid chemical compound, FFDH may be transported across the cell membrane to detect Cu2+ in vivo. It is of great significance in many fields, such as biology, biochemistry, medicine and environment.

Synergistic effect of MWCNTs-COOH and Ag nanoparticle on improving thermal conductivity of hybrid nanofluid has been explained experimentally in this paper. Different concentrations of MWCNTs/water nanofluids (0.004, 0.008, 0.04 and 0.16 vol%) were used and mixed with (0.04 vol%) Ag nanoparticle to prepare hybrid nanofluid. TEM was employed for confirming the size of MWCNTs and Ag nanoparticles in base fluids. Furthermore, SEM and XPS were utilized to characterize the prepared hybrid nanofluid. The hybrid nanofluids’ thermal conductivity was measured in varying volume fractions at 20–50 °C temperatures. As shown by the results, the ratio of thermal conductivity of hybrid nanofluids is increased in a nonlinear manner as the concentration and temperature increase. It was seen that the hybrid nanofluid’s thermal conductivity having 0.04 vol% Ag nanoparticles and 0.16 vol% MWCNTs was synergistically improved by 47.3% in comparison with thermal conductivity the water base fluid. In the end, new thermal conductivity ratio correlation was suggested on the basis of the empirical data. Comparisons of correlation output and experimental thermal conductivity ratio data showed high accuracy and capability in modeling of thermal conductivity ratio data.

The hydration and swelling of shale formations are serious problems for well drilling. The use of an efficient shale inhibitor is one of the most important methods for overcoming the wellbore insta...

International audience; Non-isocyanate polyurethane-ureas (NIPUUs) are a greener alternative to the traditional isocyanate-based polyurethane-ureas. These materials are synthesized by transurethanization and aminolysis of cyclic carbonate, commonly performed in solvents and in bulk. For several reasons including scalability, properties and environmental impact, there is a growing interest in developing water-based NPUUs. This review aims at discussing the achievements and the remaining challenges in the development of water-soluble NIPUUs, NIPUUs-based hydrogels as well as water-borne NIPUU dispersions.

Colloidal particles removal from water is a challenge in surface water treatment. Previously, we suggested an original technique for colloidal particles separation from water based on physical flow manipulation by an oscillating device. Laboratory experiments and 2D numerical simulation indicated that this technology enhances colloidal particles grouping and enables their rapid, simultaneous aggregation and sedimentation. The 2D model used in that study was unable to fully elucidate the grouping mechanism, settling pattern, or particle trajectories. Here, we extended the numerical simulation from 2D to 3D and examined the system’s distinctive flow field. The flow field was solved with computational fluid dynamics (CFD) simulations in the commercial ANSYS Fluent code and validated by dye injection experiments. The sedimentation patterns could nicely be explained by the computational results. This explanation was strengthened by two-dimensional population balance model simulations, which showed that particles aggregated in two zones trailing the paddle edges. Additionally, the results indicate significantly higher TKE values and faster upward vertical velocities at the higher oscillating frequency, which explains the different sedimentation patterns and removal efficiencies generated by the different oscillation frequencies. The use of 3D numerical simulations will help to better understand and further optimize this novel technology.

As a new type of carbon material, carbon dots (CDs) with exceptional properties are regarded as a type of potential water-based lubricant additive. In this study, it is first demonstrated that CDs perform excellently when used as lubricant additives for water-lubricated amorphous carbon (a-C) contacts. The results show that the introduction of CDs into water at a concentration of 0.1 wt% could reduce friction and wear in a-C contacts by 33% and 80%, respectively. Additionally, the lubricating performance of CDs is highly sensitive to its adding concentration. The excellent tribological performance of CDs results from the minimized CDs sediment particles (deposited in situ on worn a-C surfaces) and the reduced friction and wear via nano-bearing and nano-filling mechanisms. With high CDs concentrations, however, micron and submicron-sized sediment particles form when friction occurs and cause undesirable abrasive wear. For water-lubricated a-C contacts, therefore, the CDs concentration is the crucial determinant of lubrication performance that has to be appropriately controlled.

Water-based liquid scintillators (WbLS) present an attractive target medium for large-scale detectors with the ability to enhance the separation of Cherenkov and scintillation signals from a single target. This work characterizes the scintillation properties of WbLS samples based on LAB/PPO liquid scintillator (LS). X-ray luminescence spectra, decay profiles, and relative light yields are measured for WbLS of varying LS concentration as well as for pure LS with a range of PPO concentrations up to 90 g/L. The scintillation properties of the WbLS are related to the precursor LAB/PPO: starting from 90 g/L PPO in LAB before synthesis, the resulting WbLS have spectroscopic properties that instead match 10 g/L PPO in LAB. This could indicate that the concentration of active PPO in the WbLS samples depends on their processing., 6 pages, 7 figures, 2 tables. Submitted to Materials Advances, a journal of the Royal Society of Chemistry

In present work, five different nanoparticles of three different shapes are used to study the enhancement in thermal conductivity, viscosity and stability of nanofluids. The main objective of present work is to analyze the effect of shape on thermo-physical properties of nanofluids. For this study, spherical, cubic and rod shaped nanoparticles are used. CuO, MgO, TiO2, ZrO2 and Al2O3 water based nanofluids are prepared by two step method using probe sonication technique. The effect of shape on thermal conductivity of nanofluids is analyzed experimentally by using hot-wire method set up. Results of this study reveal that the cubic shaped Al2O3 nanofluid (concentration 2.5 wt%) shows highest thermal conductivity over base fluid by 3.13 times. Effect of nanoparticle shape on the viscocity is also studied in the presnt work. Al2O3 nanofluid also has good stability amongst all nanofluids. Also, it is observed that in all five cases of nanofluid cubic shape nanoparticles enhance thermal conductivity at the highest rate than spherical and rod shape. Pumping power study shows that cubic shaped nanoparticles require higher pumping power than spherical and rod shaped nanoparticles.

The exceptional underwater adhesive properties displayed by aquatic organisms, such as mussels (Mytilus spp.) and barnacles (Cirripedia spp.) have long inspired new approaches to adhesives with a superior performance both in wet and dry environments. Herein, a bioinspired adhesive composite that combines both adhesion mechanisms of mussels and barnacles through a blend of silk, polydopamine, and Fe3+ ions in an entirely organic, nontoxic water‐based formulation is presented. This approach seeks to recapitulate the two distinct mechanisms that underpin the adhesion properties of the Mytilus and Cirripedia, with the former secreting sticky proteinaceous filaments called byssus while the latter produces a strong proteic cement to ensure anchoring. The composite shows remarkable adhesive properties both in dry and wet conditions, favorably comparing to synthetic commercial glues and other adhesives based on natural polymers, with performance comparable to the best underwater adhesives with the additional advantage of having an entirely biological composition that requires no synthetic procedures or processing., New mussel‐inspired, high‐performance underwater adhesive is developed using Bombyx mori silk fibroin as protein backbone and polydopamine as catechol bearing molecule. This all‐natural synthetic‐step free composition displays in lap‐shearing bonding tests underwater adhesion forces (2.6 MPa) that rival commercial synthetic adhesives.

In many aspects the past decade has proved the rapid development of water based and oil based nanofluids science. Number of research is conducted to estimate the behavior of these fluids in the different thermal equipments. However, nanofluid viscosity deserves much attention during the application of nanofluids. The existing experimental result about the viscosity of nanofluids shows clearly that the viscosity augmented accordingly with an increase of additive concentration and decreased with the temperature rise. In this paper, different characteristics of viscosity of nanofluids are compiled and the viscosities of Al2O3-water nanofluids are estimated by Matlab approximation.

A simple and low-cost bottom-up method for the preparation of water-soluble Carbon dots (CDs) by tuning the carbonization degree of ammonium citrate. The structure and morphology of CDs were characterized by Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). And the investigation on the lubricating property and inhibition effect of CDs as nanoadditives of water-based lubricants is discussed in this work. The results show that the CDs as eco-friendly nanoadditives exhibit low friction coefficient, outstanding wear-resistance and excellent inhibition effect.

In order to apply the excellent properties of carbon nanotubes to the field of biomedicine, water-based high concentration carbon nanotubes(CNTs) slurry with high dispersibility and stability was prepared by adjusting illumination conditions and pH values. The infrared spectroscopy, zeta potential, TEM and digital camera were used to investigate the effect of illumination conditions and pH values on the dispersibility and stability of the CNTs slurry. The results show that the CNTs slurry has more functional groups and can be sufficiently oxidized in the absence of light than in the natural and intense light conditions. And the higher light intensity used for oxidation treatment caused a decrease of the functional groups and the surface activity of the CNTs in the slurry. The increase of the pH value can promote electrostatic repulsion, and the enhancement of light intensity can decrease the electrostatic repulsion. So, the CNTs individuals oxidized in the absence of light possessed high dispersibility and stability as varying pH value from 11.5 to 4, which slurry concentration is 10 wt% and no CNTs settlement was observed for nearly one year. However, the CNTs in the water-based carbon nanotube slurry prepared under other illumination conditions re-agglomerated and settled after several days, especially when the pH value is below 4.

With the aim to analyze pollutant in water, an effective photocatalytic microreactor has been presented in this paper. The microreactor was made of soda-lime glass, and square wave microchannels we...

Micro/nanomotors that could convert chemical energy into autonomous motion to perform various tasks are the most active research areas in chemical engineering. Up to now, the majority of micromotors require complex procedures and expensive Pt as catalyst for propulsion, which hinder seriously their practical application. Herein, we demonstrate a facile biotemplate route to synthesize a novel Pt-free temperature-responsive micromachine with fascinating recognition, capture and release capacities for erythromycin in water based on the integration of surface imprinted technology, the temperature-response of poly (N-isopropylacrylamide) (PNIPAM) hydrogels, and the autonomous motion ability of micromotor. The resulting Janus micromotor not only exhibited high temperature-controlled recognition and adsorption capacities than most reported erythromycin-imprinted materials, but also revealed high trajectory control ability and easy recovery by an external magnetic field, showing great potential for biomedical and water purification applications.

The natural water has frequency dispersion and its permittivity is also related to temperature, which are important factors to design temperature insensitive absorber at microwave frequency. Here, a water-based metamaterial absorber which is fabricated by 3D-printing is proposed. The absorber can perform stably at different temperatures and it also shows 90% absorption in the frequency range of 7.9–21.7 GHz. The experiment proves that the absorber can work at a wide incident angle and is polarization insensitive. Based on these features, the water-based absorber could be applied to various electromagnetic scenarios such as stealth technology and electromagnetic compatibility in temperature-variable environment.

In water based solutions, electrodeposition of Pd and Pd alloys is complicated due to hydrogen embrittlement. This can be avoided by using non-aqueous solutions like deep eutectic solvents ...

This study explores an electrochemical adsorption method on the regeneration of aqueous drilling fluid waste. Response surface analysis was applied to investigating the electrochemical factors on t...

The purposes of the work are to fabricate novel environment-friendly water-based polyamide-imide (PAI)-graphite-LaF3 bonded solid-lubricating coatings (BSLCs), and investigate the corresponding tribological properties and mechanisms. The experimental results reveal that the preparation of the water-based PAI-graphite-LaF3 BSLCs has significantly reduced the usage of organic solvent. When the mass percent of nano-LaF3 is 5 wt%, the water-based PAI-graphite-LaF3 BSLCs exhibit superior mechanical and tribological properties, which are comparable to those of the reported organic-solvent-based BSLCs. The tribological mechanisms were systematically investigated concerning the failure mechanism, the tribological reactions and structural fluctuations of graphite.

We studied the effect of polymer design on the interfacial structure and physical properties of polymer films in water based on a poly(vinyl ether) platform with hydrophilic side-chains to construct bioinert interfaces. Initially, we explored how to prepare hydrophilic surfaces using poly(vinyl ether)s, utilizing the preferential segregation of a rubbery component in a diblock copolymer film with a glassy component, crosslinking a hydrophilic polymer, and designing an interfacial modifier with a special architecture. Characterizing the interfacial structure and physical properties of the obtained polymer films in water revealed that a small difference in the side-chain structure significantly impacts the resultant interfacial properties of the polymers, leading to excellent blood compatibility. Furthermore, we demonstrate that swelling behaviors, which are related to chain dynamics, at the water interface play a key role in determining bioinert properties. The effect of polymer design on the interfacial structure and physical properties of polymer films in water based on a poly(vinyl ether) platform with hydrophilic side-chains was examined to construct bioinert interfaces. Hydrophilic surfaces were prepared by utilizing the preferential segregation of a rubbery component in a diblock copolymer film with a glassy component, crosslinking a hydrophilic polymer, and designing an interfacial modifier with a special architecture. Interfacial structure and physical properties controlled by polymer design play important roles in determining bioinert properties.

Ultrathin silver nanowires (UTAgNWs) are indispensable to achieve transparent conductive films (TCFs) with overall optoelectronic performance exceeding that of the state-of-the-art indium tin oxide films. Impurities in raw UTAgNW products severely impair the optical properties of TCFs. Unfortunately, highly effective and environment-friendly approaches for purification of UTAgNWs are still lacking. Herein, we report the purification of UTAgNWs using deionized water along with a small amount of surfactants as the purifying agent. TCFs coated with the purified UTAgNWs exhibit a light transmittance of 97.9% and a haze of 1.22% at a sheet resistance of 36.3 Ω sq

A novel water-stable coordination polymer, {[Zn(L)(dpa)]·(ClO4)} (CP 1) (L = 3-carboxy-1-(3-carboxybenzyl)pyridin-1-ium, dpa = 1,2-di(pyridin-4-yl)ethane), was synthesized under hydrothermal conditions by a zwitterionic organic ligand and fully characterized. This is the first water-stable coordination polymer based on the zwitterionic type of organic ligand that can selective, sensitive, and recyclable detect ascorbic acid in aqueous phase.

In this article, the unsteady free convection flow and heat transfer of nanofluid past over an infinite vertical plate is considered. The fractional generalized Fourier's law with Caputo time derivatives with power-law model to describe the influence of memory on the nanofluid behavior. The analytical solutions for dimensionless temperature and velocity fields and dimensionless thermal flux are obtained by means of Laplace transformation. The fluid is water based nanofluid containing nanoparticles of CuO or Ag. The effects of fractional and physical parameters are discussed graphically.

Summary In recent years, drilling fluids have become more complex in nature to satisfy diverse requirements in drilling operations. Accurate prediction of the frictional pressure losses while drilling is complex because of a combination of various drilling parameters. In the present study, a computational–fluid–dynamics (CFD) analysis is performed to investigate the hydraulics of solids–free non–Newtonian drilling fluids with an eccentric annulus coupled with a rotating drillstring. The Herschel-Bulkley fluid model is used to describe the non-Newtonian fluid behavior of the drilling fluid. Annular inlet fluid velocities are varied from 0.5 to 1.2 m/s (laminar flow). Simulation results are compared with the experimental data from the in–house flow–loop results. The flow loop has a 10–m–long annulus section with a 100–mm–inner–diameter (ID) wellbore and 50–mm–outer–diameter (OD) fully eccentric drillstring. Pressure–drop results from the flow–loop experiments at various flow velocities with and without drillstring rotation are reported. Experimental results show that the pressure drop increases with the drillstring rotation in an eccentric annulus. Pressure–drop predictions from CFD analysis are in close agreement with the experimental results. Also, it has been observed that drilling fluids with similar viscosity profiles measured according to API RP 13D (2017) can have significantly different hydraulic and cuttings–transport behavior. As observed from experimental results, drilling fluids with similar viscosity profiles and density have different pressure drops. This study will contribute to a better understanding of the hydraulic behavior of drilling fluids.

Inadequate hole cleaning often leads to challenges in drilling and well completion operations such as low rates of penetration, pipe sticking, losing tools, difficulties in liner/casing placements, etc. Designing a drilling fluid with improved rheological properties would be a solution to increase cuttings transportation efficiency. This study investigates the performance of nanosilica water-based drilling fluids for the hole cleaning process in directional drilling operations. Different inclination angles have been considered in a flow loop system with different rotational speeds (0 and 150 rpm) to simulate the drilling conditions in a wellbore. The performance of nano-enhanced drilling fluids in the cuttings removal process was compared with conventional water-based drilling fluids, and it was found that silica nanoparticles increased the cuttings transport efficiency in all experiments. The results indicated that the presence of nanosilica in the mud increased the colloidal interactions with cuttings and contributed to the improvements in cuttings transportation efficiency by 30.8–44% for different nano-enhanced water-based drilling fluids used in this study. The implementation of nanosilica in water-based drilling fluids showed promising results in the hole cleaning process which demonstrates the feasibility of using them in extended reach drilling operations.

The effect of electrolyzed water in controlling the setting behavior of cement paste was investigated in this study. The distilled, as well as the 30 min electrolyzed water, was used to prepare the cement paste. Analyzing the results, the final setting time of control cement (CC) paste, as well as the 30 min electrolyzed water based cement (EC) paste, was measured to be 172 ± 5 min and 108 ± 4 min, respectively. The reduction of setting time is due to the quick hydration of cement clinkers. Based on the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis, the early setting and hydration performance of cement has been justified.

The polyethylene glycol (PEG) modified carbon dots (CDs-PEG) were facile synthesized by one-pot pyrolysis of the mixture of gluconic acid and PEG. When the average molecular weight of PEG was 200, ...

In the 1980s, a new class of thickeners, i.e., associative thickener (AT), was introduced for water-based coatings to improve their rheology. Principally, they work by associating with polymer particles present in the paint. Manufacturers of ATs provide some generic guidelines to choose them based on economy, regulatory restrictions, and polymer type; however, it is very difficult to choose suitable ATs until and unless their interactions with polymer particles are studied by rheology. This article focuses on developing a rheological approach to identify a suitable AT for a paint formulation. In this approach, a rheology viscosity curve was used on AT–emulsion polymer mix and AT–emulsion polymer–surfactant mix to short-list a suitable AT. Subsequently, the shortlisted ATs were tested in the paint formulation to study their efficacy. Commonly used, hazardous air pollutants (HAPs)-free, commercially available ATs, viz. hydrophobically modified ethoxylated urethane thickener (HEUR) and hydrophobically modified poly(acetal- or ketal-polyether) thickener (HMPE), were selected to study their interaction with a unique surfactant-stabilized acrylic–polyurethane hybrid emulsion. A range of acrylic–polyurethane hybrid emulsions were prepared by increasing the polyurethane content in the emulsion. As the polyurethane content increased in the emulsion polymer, the thickening efficiency of AT decreased.

The authentication of the documents by experts mainly depends on determines the chronological order of strokes intersection. The samples consist of two types of intersections of a toner laser printer and water-based ink. Two nondestructive methods; digital microscope and Raman spectroscopy were used in the samples investigated. The effect of variations in the brands and models of laser printers, the influence of changes in brands of water-based ink, the nature of the paper surface and a time gap between the first and the second strokes on the determination of the sequence of intersecting strokes were studied. The four physical characteristics investigated under the digital microscope; the specular reflection, the ink glosses, gap and spreading determine the sequence of intersecting strokes except in case some colors of some pen brands. The results of Raman spectroscopy detect the sequence of intersecting strokes regardless of the colors or pen brands. The combination of a digital microscope and Raman spectroscopy can be considered as a scientific forensic base to determine the sequence of intersecting strokes of water-based ink and toner.