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A linear stability analysis is performed for the onset of Marangoni convection in a horizontal layer of a nanofluid heated from below and affected by rotation. The top boundary of the layer is assumed to be impenetrable to nanoparticles with their distribution being determined from a conservation condition while the bottom boundary is assumed to be a rigid surface with fixed temperature. The motion of the nanoparticles is characterized by the effects of thermophoresis and Brownian diffusion. A modification model is used in which the effects of Brownian diffusion and thermophoresis are taken into consideration by new expressions in the nanoparticle mass flux. Also, material properties of the nanofluid are modelled by non-constant constitutive expressions depending on nanoparticle volume fraction. The steady-state solution is shown to be well approximated by an exponential distribution of the nanoparticle volume fraction. The Chebyshev-Tau method is used to obtain the critical thermal and nanoparticle Marangoni numbers. Different stability boundaries are obtained using the modified model and the rotation.

In the majority of rechargeable batteries including lithium‐ion batteries, polyvinylidene fluoride (PVdF) binders are the most commonly used binder for both anode and cathode. However, using PVdF binder requires the organic solvent of N‐methyl‐2‐pyrrolidone which is expensive, volatile, combustible, toxic, and has poor recyclability. Therefore, switching to aqueous electrode processing routes with non‐toxic binders would provide a great leap forward towards the realization of ideally fully sustainable and environmentally friendly electrochemical energy storage devices. Various water‐soluble binders (aqueous binders) were characterized and compared to the performance of conventional PVdF. Our study demonstrates that the electrochemical performance of Zn/MnO2 aqueous batteries is significantly improved by using sodium carboxymethyl cellulose (CMC) binder. In addition, CMC binders offer desirable adhesion, good wettability, homogeneous material distribution, and strong chemical stability at certain pH levels (3.5–5) without any decomposition for long‐cycle life.

"The synthetic resins in printing inks are harmful to the environment because they are not biodegradable and emit volatile organic compounds. The printing industry has sought alternative printing inks to solve these issues. The aim of the work is to explore sustainable and environmentally friendly inks, without scarifying ink performance. To determine their performance and effect on print quality, soy proteins were investigated. Also, commercial and formulated acrylic inks were used as reference inks. From the results, the print density of soy protein water-based inks is higher than that of the reference inks. Moreover, they obtained a higher print gloss than the reference inks. The printing contrast values of soy protein water-based inks are relatively low. There was no considerable difference found in TVI values. Overall, the soy protein water-based inks produced a very competitive result in printability and presented high potential for replace synthetic components in current commercial inks."

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

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.

Catfish is one of the fishery products favored by the community because of its high protein. So that Catfish is one of the fish that is the center of business for fish farmers. The pond conditions used by Catfish farmers are generally still conventional. So that the maintenance of clean water in ponds is still done manually and even escapes attention. Water conditions will affect the health and productivity of Catfish. In order to achieve the optimum conditions in the third media, a control system consisting of three types of sensors will be used, namely Flowmeter, LDR sensor and LM35 sensor. The flowmeter sensor is used to regulate the flow of water, the LDR sensor functions as a receiver that is used to detect the level of turbidity of water based on how much light enters the water (turbidity). Meanwhile, the LM35 sensor functions to detect the temperature in the media so that the optimum condition for Catfish based on temperature parameters is around 22 - 32 ° C

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.

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.

Thermal-hydraulic characteristics of water based ZrO2 nanofluids has been investigated in a segmental baffled shell and tube heat exchanger in turbulent flow regime. The effect of Reynolds number, nanoparticle loading, mass-flow rate, and tube lay-out has been analysed on overall heat transfer coefficient. The effect of Reynolds number on the tube side pressure drop and convective heat coefficient have also been discussed. The effect of shell side mass-flow rate was also investigated on shell side heat transfer coefficient determined using Bell-Delaware method. The nanoparticle volume concentration is taken very low i. e. 0.2%, 0.4%, and 0.8%, respectively. The improvement in both tube side convective heat transfer coefficient and overall heat transfer coefficient has been observed. The maximum improvement in the convective heat transfer coefficient is found to be 14.1% for 0.8% ZrO2 nanofluids. However, the percentage enhancement in tube side pressure drop was higher than the percentage increment in the tube side heat transfer coefficient.

Dynamic viscosity of SiO2/22nm nanofluids prepared in a glycerine-water (30:70 by volume) mixture base liquid, referred to as GW70, is measured experimentally. Nanofluids with concentrations of 0.2, 0.6, and 1.0 percent are produced, and viscosity measurements are carried out at temperatures ranging from 20 to 80 oC using a LVDV-2T model Brookfield Viscometer. The particle size and elemental composition of nanoparticles are determined using FESEM and EDX. XRD images confirm the SiO2 peaks in the crystalline structure. The rheology of nanofluids is influenced by the nanoparticle’s concentration. In the experimental temperature and concentration range, nanofluids show Newtonian behavior. The viscosity of nanofluids enhanced as particle concentration increased and reduced as temperature increased. For 1.0 percent vol. concentration at 20oC, the maximum viscosity value is achieved, and for 0.2 percent vol. concentration at 80oC, the lowest viscosity value is observed. The viscosity of the glycerine-water base fluid was also determined at 20, 40, 60, and 80 degrees Celsius. The viscosity ratio of nanofluids to the base liquid is found to be more than one for all the nanofluids. This viscosity data is useful to estimate HTC of glycerine-water-based silica nanofluids.

This work reports an alternative technique based on a complementary double split-ring resonator to determine the concentrations of ammonia and iron in water. The conventional methods for measuring ammonia and iron concentration involve expensive and bulky instruments in the laboratory. Furthermore, the current methods involve hazardous chemical reagents and complicated procedures. In this work, a low-cost microwave sensor which is portable and easy to operate is proposed. The water samples that have different ammonia or iron concentration is dropped deposited at the sensing area. Their concentration is determined based on the shifting of the resonance frequency in the measurement. The measurement results indicate that the resonance frequency of the resonator reduced from 2.38 GHz (unloaded condition) to a low-frequency range when the water sample containing different concentrations of ammonia or iron are introduced to the sensing area. Based on the collected results, Fourier models are used to establish the relationship between the concentrations of ammonia and iron (in the range of 0 to 53 mg/L) to the resonance frequency shifting. The validity of these models is proven as they introduced a root mean square error (RMSE) of less than 0.009. The findings of this work demonstrated the feasibility of the microwave sensor in detecting water pollutants.

The study assessed a new mobile electroencephalography (EEG) system with water-based electrodes for its applicability in time-frequency and event related potential research. It was compared to a standard gel-based wired system. EEG was recorded on two occasions as participants completed the flanker task, first with the gel-based system followed by the water-based system. Technical and practical considerations for the application of the new water-based system are reported based on the participant and experimenter experiences. Empirical comparisons focused on EEG data noise levels, frequency power across four bands including theta, alpha, low beta and high beta and P300 and ERN event related potential components. The water-based system registered more noise compared to the gel-based system which resulted in increased loss of data during artefact rejection. Signal to noise ratio was significantly lower for the water-based system in the parietal channels which impacted the observed parietal beta power. It also led to a shift in topography of the maximal P300 activity from parietal to frontal regions. It is also evident, that the water-based system may be prone to slow drift noise which may affect the reliability and consistency of low frequency band analyses. Considerations for the use of this specific system for time-frequency and event related potentials are discussed.

Applying nanomaterials and nanotechnology in lubrication has become increasingly popular and important to further reduce the friction and wear in engineering applications. To achieve green manufacturing and its sustainable development, water-based nanolubricants are emerging as promising alternatives to the traditional oil-containing lubricants that inevitably pose environmental issues when burnt and discharged. This review presents an overview of recent advances in water-based nanolubricants, starting from the preparation of the lubricants using different types of nanoadditives, followed by the techniques to evaluate and enhance their dispersion stability, and the commonly used tribo-testing methods. The lubrication mechanisms and models are discussed with special attention given to the roles of the nanoadditives. Finally, the applications of water-based nanolubricants in metal rolling are summarised, and the outlook for future research directions is proposed.

Bioinspired Biomaterials A silk cocoon is nestled within a mussel shell. Taking inspiration from the adhesive property of mussels and the assembly properties of silk materials new, water‐based, eco‐friendly glues with exceptional underwater adhesion performance can be formulated. More details can be found in article number 2004786 by Gianluca M. Farinola, Fiorenzo G. Omenetto, and co‐workers. [Image: see text]

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.

Drilling mud is used to ensure save and cost-effective drilling operations. In every phase of the drilling operation, contaminants are encountered which directly affect the properties of the drilling mud. The severity of drilling mud contamination depends on the type of drilling mud used, the type of contaminant and the degree of contamination. In most drilling operations, cement contamination occurs one or more times when casing strings are cemented and the plugs are drilled out. Drilling mud is discarded when cement contamination is too high such that it is practically unreasonable to treat it. It is therefore important to monitor the mud's properties against contamination to ensure the basic functions of the mud. To perform effective monitoring of a drilling mud requires proper knowledge of the drilling mud chemistry, properties, and contaminants. This will help oil operators to apply the right control measures and treatment methods during drilling operations. This paper presents an experimental study on the effect of various concentrations of cement contamination on some physical properties of water based mud (WBM). Four mud samples were prepared of which three of them were contaminated with 10 g, 20 g and 30 g of class G cement. Rheological properties at temperatures of 25 °C, 40 °C and 60 °C as well as the pH, fluid loss and density of the mud were determined. The findings showed that the yield point and gel strength at all test temperatures increased as the concentration level of cement increased. However, the plastic viscosity decreased slightly with cement concentration of 10 g and 20 g and further increased with 30 g of cement contamination at 40 °C and 60 °C. The fluid loss, density as well as the pH of the WBM increased gradually as the concentration of cement increased. It is recommended that the effect of cement contamination in WBM at temperatures higher than 60 °C should be investigated. Cited as : Broni-Bediako, E., Amorin, R. Experimental study on the effects of cement contamination in a water based mud. Advances in Geo-Energy Research, 2019, 3(3): 314-319, doi: 10.26804/ager.2019.03.09

Background: Lymphedema is a chronic, progressive disease consisting of tissue swelling resulting from excessive retention of lymphatic fluid. Measuring upper limb volume is crucial in patients to detect disease progression and to study the effects of treatment. The aim is to assess the validity and reliability of a newly developed system, Peracutus Aqua Meth, for measuring the upper limb volume compared with the gold standard water volumetry device. (In this study, the Bravometer was used). Methods and Results: Healthy volunteers were recruited in October 2017. Three measurements were performed per device. The obtained data were recorded per measurement, device, and researcher. Primary outcome was to determine the validity and reliability of the Peracutus Aqua Meth. Secondary outcomes were intra- and interrater reliability, measurement time, self-reported participant satisfaction, and influence of body mass index (BMI). Thirty-nine healthy volunteers were included. Mean differences in the validity in the Peracutus Aqua Meth and Bravometer were 47.26 and 78.16 mL, respectively (p = 0.04), with a Pearson's r of 0.99. Intra- and interrater reliability of the Peracutus Aqua Meth were both 0.99, in the Bravometer 0.96 and 0.97, respectively (p

The drilling campaign on Pad C of the Tiputini Field, located on the Oriente Basin, Ecuador, started with the first exploratory well TPTC-002. Pressure tests performed on the M1 sandstone of the Napo Formation determined that the average reservoir pressure (Pr) was 1921 psi. Ten months later, Pr averaged 846 psi. This increased the risk of differential pressure sticking, event that indeed occurred while drilling the well TPTC-016. By using the “Bow-Tie” methodology as a predictive tool to analyze risks, and taking into account the preliminary studies that describe this phenomena, a solution was found for stablishing an additional barrier with the use of diesel on the water-based drilling fluid. Diesel was used in order to extend the ‘half value time’ and to decrease the friction coefficient between the mud cake and pipe.

The article presents the results of experimental studies of water droplets propagation through the sample of typical forest fuel materials: needles, leaves, and their mixture. Different conditions are considered: without any additional energy supply, with heating, in the course of intensive thermal decomposition and flaming combustion. Three methods of registration are applied: thermocouple measurements, control of the weight of the sample as a whole and of its individual layers, and high-speed video recording. Water-based compositions with special additives (bentonite, bischofite, and foaming agents) typical for forest fire extinguishing systems are used. The experiments are carried out using aerosol and single water drops, as well as a small group of the latter. It is shown that the mechanisms, conditions and characteristics of droplet propagation through the layers of needles, leaves and their mixtures differ significantly. The scientific novelty of the work is the determining of the values of all the key characteristics of these processes in the conditions of intensive pyrolysis of the material, as well as through its inert layers.

This paper describes the concept of didactic communication and verifies the course of teaching selected disciplines of water based recreation, i.e. swimming (at the standard technique level), handling a sailing boat whilst undertaking simple manoeuvres, and the basics of diving. At the same time, research in the area of experiments conducted in the field of teaching methods of these disciplines was reviewed in terms of teaching effectiveness, as well as the health and safety of the participants, and ways of communicating while in, on and under the water. Communication between an instructor and a student in any environment which is different from the norm, is difficult owing to its specificity. Additionally, teaching skills on, in or under water requires strict observance of safety rules. Lack of student’s readiness to act in a different water environment, be that based on anxiety or fear, may interfere with or, even prevent didactic communication. Consequently, the effectiveness of teaching decreases. The aim of this work is to search for innovative forms of information transfer that will enable a permanent change in the student’s behaviour, especially when acting in a difficult environment – on the water, in the water and under the water. There are premises to believe that immediate verbal instruction and emphasising the metalinguistic function in it should improve the quality and effectiveness of the process of teaching activities in various water based environments.

This report will be looking at how fuzzy logic is used to create a system which automatically carbonates water to create sparkling water. This is a topic that has not been discussed a large amount and there is little about it in the associated literature. The system created in this work uses the research available to create a system that carbonates water based on the temperature of the water, the amount of water being carbonated and the sparkling preference of the user. This is then processed in the Water Carbonation Fuzzy Inferencing System (FIS) which outputs to give the Carbon Dioxide Usage. This system is made for domestic water carbonation products and could be extended to larger or smaller products of the type. Several tests have been carried out to measure the success of the system. Changes are then made, and the system is tested again to make sure that the system has been improved. Tests are continued until the system is efficient for the purpose and all the different possible parameters are checked. A critical reflection on the work illuminates the good points, limitations and where improvements could be made.

Researchers are still working on the development of models that facilitate the accurate estimation of acoustic cavitation threshold. In this paper, we have analyzed the possibility of using the incubation time criterion to calculate the threshold of the onset of acoustic cavitation depending on the ultrasound frequency, hydrostatic pressure, and temperature of a liquid. This criterion has been successfully used by earlier studies to calculate the dynamic strength of solids and has recently been proposed in an adapted version for calculating the cavitation threshold. The analysis is carried out for various experimental data for water presented in the literature. Although the criterion assumes the use of macroparameters of a liquid, we also considered the possibility of taking into account the size of cavitation nuclei and its influence on the calculation result. We compared the results of cavitation threshold calculations done using the incubation time criterion of cavitation and the classical nucleation theory. Our results showed that the incubation time criterion more qualitatively models the results of experiments using only three parameters of the liquid. We then discussed a possible relationship between the parameters of the two approaches. The results of our study showed that the criterion under consideration has a good potential and can be conveniently used for applications where there are special requirements for ultrasound parameters, maximum negative pressure, and liquid temperature.

Nanofluids are suspensions of nanoparticles in a base heat-transfer liquid. They have been widely investigated to boost heat transfer since they were proposed in the 1990s. We present a statistical correlation analysis of experimentally measured thermal conductivity of water-based nanofluids available in the literature. The influences of particle concentration, particle size, temperature and surfactants are investigated. For specific particle materials (alumina, titania, copper oxide, copper, silica and silicon carbide), separate analyses are performed. The conductivity increases with the concentration in qualitative agreement with Maxwell’s theory of homogeneous media. The conductivity also increases with the temperature (in addition to the improvement due to the increased conductivity of water). Surprisingly, only silica nanofluids exhibit a statistically significant effect of the particle size, whereby smaller particles lead to faster heat transfer. Overall, the large scatter in the experimental data prevents a compelling, unambiguous assessment of these effects. Taken together, the results of our analysis suggest that more comprehensive experimental characterizations of nanofluids are necessary to estimate their practical potential.

This research is a novel experimental work on cooling solar panels using hydrogel beads saturated with Al2O3 water based nanofluid. Nanofluid of concentrations 0.1, 0.25, and 0.5% wt. were used and compared to the water only cooled and the uncooled PV panels. A passive cooling system was created with three layers of the nanofluid saturated hydrogels and attached to the back surface of the exposed PV panels, with fixed radiation intensities of 800 and 1000 W/m2. Using 0.5%wt. Al2O3 water based nanofluid saturated hydrogels, the temperature of the panel was reduced by approximately 17.9 °C and 17.1 °C for radiation intensities of 800 and 1000 W/m2 respectively, compared to the uncooled one. From a performance point of view, 0.5% wt. gave the optimum performance; however, due to the price on the nano materials, 0.25% wt. concentration is the optimum economical selection. The economic analysis showed that the payback period, using 0.25% wt. nanofluid concentration, was 12 years for 1000 W/m2. The annual power generated showed improvement of approximately 10.1% at both tested intensities compared with the uncooled panel. The environmental analysis showed that using the proposed system and the optimised nanofluid concentration can reduce the annual CO2 emission by 7.95 tonnes and 9.76 tonnes for a solar farm of 100 square meter area at radiation intensities of 800 and 1000 W/m2.

In most gear drive applications mineral or synthetic oils are used as lubricants, which are made of fossil raw materials and are non-biodegradable. In applications located in critical environmental areas such as boats or harbors, eco-friendly lubricants are needed. As a result, a gear transmission fluid based on water is currently being developed in a research project supported by the Bayrische Forschungsstiftung (Bavarian Research Foundation). Results of former research showed that in general it is possible to use water-based lubricants in gear drives under certain operating conditions. Since water has a low viscosity compared to conventional used lubricants, plant extracts are added to generate higher viscosities. In order to avoid tribological influenced damages such as sliding wear and scuffing on the surface of gear flanks, adequate additives are needed. Different combinations of plant extracts and additives were investigated using the scuffing test A/8.3/RT according to DIN ISO 14635-1. The results show a surprisingly high load carrying capacity regarding scuffing. Additionally, two wear tests based on DGMK 377-01 were conducted with one sample fluid. A high risk of sliding wear was detected. Additionally, MTM and SRV measurements were conducted with different polymers to optimize the lubricant. The results of the wear tests help to define operating conditions for a future lubricant based on water and plant extracts. This paper aims to share the results of the performed experimental investigations and discusses the challenges regarding the development of such new lubricants.

This paper explores the strong potential of chemical mining of wastewater for markers of community-wide intake of wide-ranging harmful chemicals belonging to several usage groups: industrial chemicals, personal care products, pesticides, illicit drugs, lifestyle chemicals and prescription pharmaceuticals as a proxy for multi-chemical community-wide exposure. An estimation of chemical intake in five contrasting town/cities based in the Avon River catchment in the South-West UK was undertaken. High-resolution spatiotemporal pharmaceutical prescription databases were used for system calibration, both in terms of biomarker selection and its correction factor, as well as for the overall system performance evaluation, both spatially and temporality. Only metabolism data accounting for phase two metabolism provided correct estimates of pharma intake. Using parent compounds as XCRs (xenobiotic compounds residue) was found to overestimate exposure due to an inclusion of directly disposed (unused) drugs. Spatiotemporal trends in XC intake were observed as a result of occupational exposure (higher bisphenol A (BPA) intake during weekday), and lifestyle choices (higher cocaine and pyrethroid pesticides intake during weekend). WBE is not intended to estimate individual exposure to chemicals. It can however provide estimates at a community level, and as a result, it has the potential to be developed into an early warning system, a powerful tool for large scale screening studies identifying communities at risk and in need of high resolution individual testing at a localised scale.