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Despite of the fact that Earth’s atmosphere has abundant freshwater inform of moisture, water scarcity is one of the crucial problems especially in humid, hot, and drought prone regions. The conventional systems which extracts atmospheric water are very bulky, incompatible with the existing system, energy intensive, impractical, low water yield and expensive. These adverse effects hinder their deployment for large scale applications. In this manuscript, a water harvesting device is deigned and fabricated for extracting water from moist air. The device uses vertical copper pipes entrenched in horizontal Al fins as the condensing surfaces. All the components of the device functions on solar powered energy. The proposed device is environment friendly, compact, lightweight, low manufacturing, and maintenance cost. The device generate water with turbidity of 40 PPM. Results shows that condensation rates strongly depend on the relative humidity, saturation temperature of the moist air, and degree of subcooling. In this device, the cost of water is estimated as Rs. 10 per liter. This device is efficient for providing drinkable water in hot and humid, water scare regions globally.

Solar energy is a renewable, free, environmental friendly, and inexhaustible form of energy. A number of devices have been developed and tested to harness solar energy. The solar air-heater is one of the thermal energy conversion devices, which collects the thermal energy coming from the sun and transfers it to the air passing through it. Sun rays passing through the top glass surface strikes the absorber plate, which acts as a medium to transfer the thermal energy. Mankind has been in pursuit of technological advancement and efficiency enhancement since the inception of the solar air-heater. Over the past few years, various advancements were made in and around the absorber plate of solar air-heater so as to maximize and enhance its performance. This paper presents a comprehensive review of the recent trends and advances made in the field of SAH for improving the thermal efficiency. Besides this, other methods of performance enhancement have also been discussed.

In this paper, simulation of silica sand-water slurry is carried out through a horizontal mitre pipe bend of 0.050 m in diameter using ANSYS Fluent 16. The simulation of silica slurry was accompanied by using Eulerian two-phase model constrained with RNG K-epsilon turbulence model. The simulation was conducted using silica sand particulates of spherical size 448.5 µm for the volume fraction range 3.94–8.82%. The simulation of silica sand particulates was carried out with water properties available at different Prandtl numbers range, i.e. Pr = 2.14–5.83. The results of silica sand concentration contours and pressure drop were predicted at different mean flow velocity range, i.e. 1.78–4.5 ms−1. It was found that the slurry pressure gradient escalates with increase in Prandtl number and mean flow velocity. Finally, the concentration contours of silica sand slurry for mean flow velocity 4.5 ms−1 at different angles i.e. θ = 0°–90° across the pipe bend are reported and discussed.

In this work, a comparative analysis is provided for technological indicators of various methods of technical levitation. Later, mathematical model was formed for particular cases of the gap of electromagnetic levitation and many composite non-contact mechanisms. This analysis mechanics creates effective contactless mechanisms which help us many aspects of energy and material saving.

Condensation on surfaces with low wettability is of great significance in microfluidics and the fabrication of nanostructures. In this work, condensation process of water vapor from moist air flowing on a mesh-like surface is investigated experimentally at controlled environment condition. In order to execute condensation, temperature difference is increased between the air dew point and Cu mesh surface temperature. The hydrophobicity on mesh-like surface is enhanced using chemical texturing. The static and dynamic surface properties are moderated on this fabricated mesh-like surface with contact angle hysteresis of 16°. Thus, this type of surface is suitable for improving the performances of condensation and to extend their practical applications worldwide.

Water is essential for human survival and is considered as the most essential for our daily life. The major problem in the modern world is water scarcity and contamination of existing water resources. This study proposed a solar-based water generating device from moist air of the hot and humid region. The device is compact with high-water generating capacity per unit volume. The condensing substrate is a super-hydrophobic copper substrate which is cooled by solar-based DC power supply Peltier modules. It is demonstrated in climatic condition of July–August month in Noida and it generated 7.6 ± 2 L of freshwater per day from the atmospheric air. The device is suitable in the areas with moist air all around the year.

Moisture evaporation on porous surface has grown into a dynamic research due to the advancement in building technologies, wooden frames, water purification, baking and cooling purpose. Evaporation on a porous surface involves complex multiphysics coupling heat and moisture transport concurrently. In the present work, numerical simulation of evaporation on the porous surface is carried out on the basis of heat and moisture transport theory. Simulations are carried out using COMSOL Multiphysics software. The simulation result of this model is validated against the analytical solution ensuing good agreement. Post-validation, a parametric analysis of the evaporation on porous surface is done to compute temperature variation, relative humidity variation, mass transfer coefficient and heat transfer coefficient at various regions on the porous surface. These results are useful for sensitivity analysis of various porous materials in the mathematical modelling of evaporation on the flat surfaces.

This study investigates the thermal characteristics of the \(3\times 8\) Li-ion cell arrangement within the battery module numerically at different boundary conditions. Various parameters are considered in the current study, such as different ambient temperatures, inlet velocities, and duct sizes. The battery module is simulated in ANSYS Fluent 19. A three-dimensional computational model is established to analyze the thermal profile of Li-ion cells for different ambient temperatures. The forced air convection method is employed to study the effects of inlet velocities at different ambient temperatures. The thermal performance of the battery module is judged on the capability of the battery module to work within the optimal temperature range of \(0{-}40\,^\circ{\rm C}\). The results indicate that \(3\times 8\) Li-ion cell arrangement at higher ambient temperature ranges works within the optimal temperature range. The thermal analysis of duct sizes shows that \(15{-}20\) mm is the ideal inlet and outlet duct size for \(3\times 8\) Li-ion cell arrangement. This would further give insights into the thermal profiles of \(3\times 8\) cell arrangement, which would aid in designing efficient battery modules with cells operating within the optimal temperature ranges.

Teh primary objective of teh present work is to compare different properties of reinforced Al7075. Boron carbide and silicon carbide (available in powder form) were mixed to teh alloy in different percentages to check their TEMPeffect along wif magnesium present in powdered form. Boron carbide (also non as black diamond) was selected as it is highly robust and TEMPhas good shielding properties against neutrons, me.e., it absorbs them well. It can stabilize teh ionizing radiations and is teh third hardest non substance after diamond and cubic boron nitride. Silicon carbide was selected as it TEMPhas high strength and hardness wif good wear resistance properties. Magnesium is selected because it is teh lightest of all teh metals and TEMPhas good heat dissipation and good damping capacity. Alloy is lightweight and TEMPhas main applications in aircraft industry, automotive parts, and defence applications. Graphite crucible was preheated (to remove teh moisture) to a temperature of 200–300 °C and tan stir casted using stir casting set up. Samples were tan poured in die and tan allowed to cool down. Samples were tan collected from die and after dat mechanical properties were tested (tensile test and hardness test). SEM/EDS and XRD analyses were conducted to briefly study teh microstructure and phase of teh samples prepared.

In this paper, slurry flow characteristics of glass beads–water slurry has been studied in a pipe of 0.0549 m diameter using commercial software FLUENT. The study was carried out using Eulerian–Eulerian two-phase model with RNG K-epsilon model turbulence closure. The simulation was carried out for a glass bead particle of size 440 µm having efflux concentration ranging from 10 to 30% by volume with Prandtl fluid (Pr = 5.83) at different Reynolds number. The results of solid concentration contour, velocity contour, and pressure drop were predicted at different Reynolds numbers to analyze the slurry flow characteristics. The plot between pressure drop versus Reynolds number was plotted at different solid concentrations. The simulation results of the present study show good results with the experimental results of the literature. The present model shows the enhancement of suspension suitability of glass bead particles at a larger distance. Post-validation, parametric studies are carried out to study the effect of parameters.

Nature has many biological structures with water repellency phenomena depicting super-hydrophobicity which are observed in various plants, insects, and animals. The advancements in the broad area of biomimetics provide scope toward development and fabrication of nanotextured surfaces. With biological design, replicating adaptation and derivation from various natural environments which is referred to as “biomimetics.” Related to exceptional properties of super-hydrophobicity, researchers have recently developed and fabricated biomimetic nanotextured super-hydrophobic materials. Surface modification to prepare chemical and physical textured super-hydrophobic metallic surfaces with standard protocols so that repeatable and well-characterized surfaces can be obtained with a high contact angle, low contact angle hysteresis, bounce, and proper roll-off rate. A review-based approach is provided in this paper with developments in surface modification and fabrication of super-hydrophobic materials by various nanotextured processes.

Turbulence flow of exhaust gases improves the efficiency of the catalytic converter in the exhaust system of vehicle. In literature, additional devices are used for creating the turbulence. However, they reduce the engine performance by inducing additional backpressure. In this work, various configurations of turbulence generating device are considered for optimizing the performance of the exhaust system of vehicle such as maximum conversion efficiency of the catalytic converter with minimum back pressure at engine exhaust system. In this context, various configuration device for generating turbulence is attached before the catalytic converter for measuring back pressure and analysing the exhaust of four-cylinder 1400-cc diesel engine. The flow of exhaust is visualized using commercial software Fluent for knowing effect of device configuration on the flow pattern. It has been found that the turbulence device with swirl blade configuration is more effective in improving the conversion efficiency of the catalytic converter at low back pressure as compared to other configuration of devices. Therefore, the swirl blade turbulent device is effective and efficient.

The hydrophobicity of the nano-coating developed with TiO2 and SiO2–TiO2 nanoparticles in organic binder is investigated, where polyurethane was taken as model binder. Core SiO2 nanoparticles have been synthesized using Stober method with average particle size of 92 nm. TiO2 and nano-core@shell have been prepared using peptization process. Particle sizes were measured as 75 nm for TiO2 and 144 nm for core-shell nanoparticles which were prepared using peptization process. In this process, hydrophobic titania was produced at 70 °C. Here, SiO2–TiO2 core–shell nanoparticle was synthesized because core silica improves the mechanical strength and shell TiO2 on core silica provides the hydrophobicity of the coating surface. Characterization of these nanoparticles was performed by UV-vis spectrophotometer, dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and XRD. The coating formulations were developed with the aforementioned nanoparticles separately and concentration of nanoparticles was varied from 1 to 6 wt%. The best performance in terms of hydrophobicity was obtained with 4 wt% of the concentration of nanoparticles in polyurethane-coating system. In this work, prepared coatings were applied on glass substrate (20 × 20 × 10 mm) using a brush, dried in oven at 80 °C for 15 min, on drying, 100-μm-thick film was obtained. Static contact angle of water droplet on these dried films was measured and obtained as 129° for PU film-containing TiO2 nanoparticle and 133.3° for PU film with SiO2–TiO2 core@shell nanoparticle.

Catalytic convertor plays an important role in reducing harmful emissions in the form of NOx, HC, and CO. Various technologies have been developed to reduce vehicular emissions; however, it comes with the expense of engine performance and cost. In this research, harmful emissions from the exhaust gases of diesel engines are reduced without compromising the engine efficiency and cost-effectiveness. In this context, a new monolith is designed and fabricated with copper–nickel alloy (constantan wire) as catalyst enclosed by an aluminum casing. This device is tested on a single cylinder diesel engine at 1500 rpm and it shows 60% NOx, 60% CO, and 35% HC conversion efficiency. This research is helpful for partial replacement of the platinum-grade material used in the present catalytic converter.

The check valve and non-return valve are specially designed valves for permitting only unidirectional fluid flow and are employed as a measure of safety for the protection of expensive equipment such as compressor, rotating parts, feed pump, and discharge reservoir. This crucial significance of nozzle check valve gives rise to its exhaustive and thorough study to meet safety standards and ISA valve specifications. The valve design primarily comprises of generating a converging and diverging fluid flow across the valve’s inner geometrical surface by keeping least surface area around the valve disc at fully opened position. To better predict the valve’s performance, this paper manifests the numerical simulation of fluid flow in a twelve-inch nozzle check valve and calculates its flow coefficient (Cq). The steady-state 3D Navier-Stokes equations with appropriate boundary conditions are numerically solved using FVM method. The computational domain consists of a 10-D and 7-D length of pipe attached to the inlet and outlet section of the valve, respectively, to capture flow development where D is the diameter of pipe. The simulation is carried for incompressible fluid (water) at numerous Reynolds numbers (3.1E4–9.3E5). Consequently, the velocity and pressure contours are plotted at corresponding Reynolds numbers, and the analysis of flow through the valve for estimating flow coefficient of the valve (Cq) is 2863 ± 5%. It is found that the flow coefficient remained constant for various Reynolds numbers. Hence, the flow coefficient is only a strong function of the shape of valve.

Heating, ventilation and air conditioning (HVAC) of hospitals is a highly specialized field and critical care units like isolation rooms and operation theatres deserve special attention, as infected patients must be isolated from ambient environment in order to prevent the infection from spreading and to save the life of the patient. This manuscript aims to optimize the ventilation strategy towards contaminant suppression in the isolation room. 3D Navier-Stokes and energy equation using finite volume method (FVM) with a domain of isolation room is solved for appropriate boundary conditions. The patient’s body is approximated as a semi-cylindrical shape resting on a bed and is treated as a constant heat source. Velocity and temperature profile inside the isolation room for various configurations are simulated. Our results suggest that immune-suppressed patients should be kept near the air supply and infectious patients near the exhaust.

This study calculates the rheological disease factor from stain patterns of blood microfluidic drop samples of patients. The work explores programmed recognition of infection from the specimen of dried miniaturized scale drop blood stains from a patient’s pathological examination. In this novel pathological examination proposed in this study less than 10 micro liters of blood is required. This strategy has the benefit of being significantly affordable and low cost, effortless and less intrusive, entirely robust for disease screening in infants and the old. Infection affects the physical and mechanical properties of biological fluid (blood), as reported by many medical and fluid mechanics fraternity previously, which thus influences the specimen of dehydrated blood miniaturized scale beads. For instance, low platelet index causes a drop in viscosity (one of the mechanical properties of the biological fluid—blood) due to blood thinning. Thus, the blood miniaturized scale drop stain specimen can be utilized for screening infections. This study proposes a programmed investigation of the dehydrated small-scale droplet blood stain specimen utilizing machine vision and pattern and feature extraction and recognition. The specimens of small-scale drop blood stains of ordinary healthy people are discernible from the specimen of miniaturized scale drop blood stains of unhealthy people. As a contextual investigation, the miniaturized scale drop blood stains of TB infected have been contrasted with the small-scale drop blood stains of healthy noninfected people. This study dives into the fundamental fluid mechanics behind how the specimen of the dehydrated small-scale drop blood stain is shaped. A thick circular boundary in the dehydrated small-scale drop blood stains of healthy people and thin crack or ridge lines in the dehydrated small-scale drop blood stains of those infected with tuberculosis have been observed. The circular boundary is because of microfluidic channel stream, an outward current conveying blood cells suspended in plasma to the periphery. Concentric formed circles (brought about by internal Marangoni stream) and inner depositions are a few of the other stain patterns that were seen in the dehydrated small-scale drop blood stain specimen of typical noninfected people.