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This paper provides a comparative numerical analysis of unsteady hybrid nanofluid (Ag + TiO 2 /H2O) and nanofluid (TiO2/H2O) flows through a permeable linear stretching cylinder placed in a porous medium has been presented in the presence of oblique Lorentz force. The flow regulating boundary layer equations has been governed due to the sway of the suction, viscous-Ohmic dissipation, heat source, thermal radiation and first-order velocity slip with imposing convective boundary conditions on the surface. The self-similar transformation has been employed to convert the governing coupled nonlinear PDEs into a set of ODEs and finally solved them numerically by fifth-order Runge–Kutta method with shooting technique. Finally, a comparative study has been made on the thickness of the momentum and thermal boundary layers due to the effect of governing parameters for simple and hybrid nanofluids. Further, a numerical observation on local skin friction and thermal-transport coefficients is presented with the help of tables. The result indicates that the progressiveness of the velocity profile reduces for the unsteadiness parameter, Hartree pressure gradient, velocity slip parameter, inclination parameter, porous medium parameter, magnetic parameter and suction parameter while improving for velocity ratio parameter and temperature profiles increases with Biot number, Eckert number, heat generation parameter and thermal radiation parameter, but decreases for Hartree pressure gradient and velocity ratio parameter. This work has found various applications in high-temperature and cooling processes, paints, conductive coatings, medicines, space technology, biosensors, conductive coatings and so on. [ABSTRACT FROM AUTHOR]

The stability of nanofluid flow in a vertical channel packed with a porous medium is examined for the local thermal nonequilibrium state of the fluid, particle, and solid-matrix phases. The effects of Brownian motion along with thermophoresis are incorporated in the nanofluid model. The Darcy-Brinkman model for the flow in a porous medium and three-field model, each representing the fluid, particle, and solid-matrix phases separately, for the temperature is used. A normal mode analysis is used to obtain the eigenvalue problem for the perturbed state, which is then solved using the Chebyshev spectral collocation technique. The critical Rayleigh number and corresponding wavenumber are presented graphically for the effect of different local thermal nonequilibrium parameters. It is noticed that the influence of local thermal nonequilibrium (LTNE) parameters on convective instability is significant. [ABSTRACT FROM AUTHOR]

The time has come when we have to rethink our destructive habits, polluting behaviors, and the nature of dealing with contemporary livelihood and lifestyle. To do that United Nations (UN) has formulated Sustainable Development Goal No. 3 ('Good Health & Well-being'). To clean the environment and to save nature, Govt. of India has developed the concept of the Swachh Bharat Mission (SBM). Actually, it is a reform of the Gandhian Mission of Swachhata. Actually, Swachh Bharat Mission is a vast and valid cleanliness program of India to stop Open Defecation (OD) at a public place, to save the women's self-esteem, to reduce the pollution due to Open Defecation, etc. in this way Swachh Bharat is a well-being project of India to make a healthy Indians. Actually, the well-being philosophy is going to be generated by the United Nations and there is no alternative way of Sustainable Development to save the earth. Recently every Govt. should formulate well-being planning to develop their civilization in a sustainable way. Swachh Bharat is not only the project to construct the 100 percent toilet, servicing in India, moreover, but it can also protect the SDG Goal No. 14 ('Life below Water') and SDG Goal No. 11 ('Sustainable Cities & Communities'), and SDG Goal No. 15 ('Life on Land'). Swachh Bharat also indicates to clean the local environment, manage the solid waste. If local people are cleaning their environment properly then the life on land will be saved from different types of pollution and radiation which are generated from radioactive solid items. A case study has been done here on Raiganj Municipality to emerge the actual scenario of the Swacch Bharat and Nirmal Bangla Project. This case study has revealed that people of this town are not aware of the well-being of Swacch Bharat and Nirmal Bangla Project. Total 13 open-air urinations locations have been pointed through field survey and presented proper photographs and map to emerge the real mental health and probable effects on physical health. To success the mission of 'Good health and well-being' only the concept of 'Sustainable Thinking' (the term was first coined by Tapas Pal on 2020) should be promoted at family to global level. [ABSTRACT FROM AUTHOR]

The convection in a vertical channel filled with a porous medium saturated by a nanofluid is studied numerically. The effects of Brownian motion and thermophoresis are incorporated in the model used for nanofluid. Also, the flow within the porous region is governed by Brinkman's equation. The generalized eigenvalue problem for the perturbed state is obtained from a normal mode analysis and solved using the Chebyshev spectral collocation method. The Rayleigh number is expressed as an implicit function of the wavenumber with other parameters. The critical wavenumber and the critical Rayleigh number are calculated for different parameters. The preferred modes under critical conditions are detected. [ABSTRACT FROM AUTHOR]

Abstract This work presents a broad study of transparent and conducting Al-doped ZnO (AZO) thin films that could replace indium tin oxide (ITO) as transparent electrode in optoelectronic devices. AZO thin films are deposited by pulsed DC magnetron sputtering at a sputtering power of 80 W with different pulse frequencies in the range 50–100 kHz. Diffraction data confirm formation of doped ZnO and AZO thin films exhibit preferred orientation in the c -direction. The crystallite sizes of Al:ZnO are in the range 16–21 nm. The field emission scanning electron microscopy and atomic force microscopy of AZO thin films reveal nucleation and growth of uniform and dense films with better quality films deposited at a pulse frequency 75 kHz. A simple and non-destructive optical method is adopted to determine thickness and dispersion parameters such as dispersion energy, carrier concentration to effective mass ratio, and plasma frequency. AZO thin films offer excellent visible light transparency and limited transparency in the near-infrared region due to free carrier absorption. The sheet resistance of AZO thin films is recorded in the range 9–45 Ω/sq making these transparent conducting oxides (TCOs) suitable for optoelectronic applications. The figure of merit as high as 1.99 × 10−2 Ω−1 is achieved for AZO thin film deposited at a pulse frequency of 75 kHz. AZO thin film sputtered with a pulse frequency of 75 kHz is quite stable in ambient oxidizing environment and surface adsorption sites might govern the initial oxidation of films when exposed to atmosphere. Excellent figure of merit and good stability of sputtered AZO thin films as TCO fulfill the requirements of a transparent electrode in photovoltaics. Graphical abstract Unlabelled Image Highlights • AZO thin films demonstrate high figure of merit as transparent conductors. • Low sheet resistance in the range 9–45 Ω/sq • Average transmittance in the range 81.4–85.1% for the wavelength range 400–700 nm • Pulsed DC sputtering capable of producing uniform and stable indium free TCO • Pulse frequency has profound effect to manipulate film growth. [ABSTRACT FROM AUTHOR]

The effect of variable gravity on the onset of convection in a horizontal porous layer has been analyzed due to external heating. The third kind of thermal boundary conditions is considered on both the boundaries which are connected by Biot numbers B 0 and B 1. Also, the Brinkman model has been employed in the momentum equation. Further, linear and quadratic varying downward gravity fields depending on height have been taken to investigate the above observation. The bvp4c scheme is used in MATLAB to solve the eigenvalue problem for neutral stability mode. It is observed that the system's stability increases monotonically due to the rising effect of gravity variation parameter, Darcy number, and Biot numbers. Further, the onset of convection has been discussed for the two limiting cases of external heating on the boundaries where one boundary is associated with constant heat flux while another one is associated with an isothermal state. Finally, it is observed that the convection comes earlier for quadratic varying gravity field compared to linear varying gravity field when the external heat supplies from one boundary or both boundaries. [ABSTRACT FROM AUTHOR]

This work demonstrates an exploration of the dynamics of the photogenerated electrons and holes in the S-scheme heterojunctions of CuO nanoparticles and ZnO microrods in the presence of plasmonic Ag nanoparticles. Herein, n-type ZnO microrods developed by the cost-efficient thermal decomposition method are decorated with nanoparticles of CuO and Ag deposited by the direct current magnetron sputtering. Microstructural analyses based on XRD, FESEM, and FETEM measurements reveal interfaces of single crystalline wurtzite ZnO with phase pure CuO and polycrystalline Ag nanoparticles. XPS results complement microstructural information from the FETEM measurements, signifying plasmon loss features of Ag nanoparticles and suggest direct electron transfer from Ag to ZnO, where ZnO microrods constitute the major part of the photocatalysts. The plausible schemes of light collection, carrier generation, and transfer have been presented based on the structural and optical properties, which are utilized to explain the photocatalytic degradation of aqueous cationic Rhodamine 6G under UV-Vis-NIR illumination. The optimized CuO-ZnO heterojunction is highly efficient as a photocatalyst with a degradation rate of 89% due to a greater light collection ability and S-scheme based electron-hole separation at multiple junctions. The plasmonic modulation of the photocatalytic activities of the heterojunction-heterostructure systems is critically governed by the structural organizations of the materials. [Display omitted] • Integration of plasmonic Ag and CuO-ZnO S-scheme heterojunction as photocatalysts. • Insights into photoexcited carrier generation, transfer, and utilization in diverse configurations. • XPS analyses of heterojunction-heterostructure photocatalysts. • Plasmon induced modulation of charge separation at multiple interfaces of Ag and CuO with ZnO. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dry method of fabrication of Ag nanoparticles and ZnO microrods heterostructure. • Preferential nucleation of Ag nanoparticles in proximities of ZnO microrods. • Seed assisted growth of ZnO microrods at higher gas pressure and shorter duration. • Near-UV (380 nm) emission enhancement possibly due to exciton-plasmon interaction. • Nearly 3-fold enhancement of near band edge photoluminescence from ZnO microrods. This work presents a physical vapour-based fabrication of an exciton-plasmon system via depositions of ZnO microrods (ZnOµRs) and Ag nanoparticles (AgNPs) on glass and p-type Si substrates. Pulsed DC sputtering of ZnO at a relatively higher Ar pressure and varying applied power enables deposition of ZnOµRs on ZnO seed layers. Sputtering of Ag ensures fabrication of AgNP/ZnOμR heterostructure with good adhesion suitable for device realization. Microstructural analyses confirm formations of wurtzite ZnOμRs and f.c.c. AgNPs. AgNPs are observed as isolated clusters due to preferential nucleation in the proximities of ZnOµRs. UV–vis absorption spectroscopy reveals broad surface plasmon resonance (SPR) of Ag NPs around 538 nm, which experiences a bathochromic shift in AgNP/ZnOμR heterostructure. The photoluminescence (PL) spectra of AgNP/ZnOμR heterostructure suggest a 3-fold enhancement of narrow near band edge (NBE) emission attributed to the exciton-plasmon interaction. [ABSTRACT FROM AUTHOR]

The influence of the Soret parameter, variable gravity field and viscous dissipation on the stability of convection with double-diffusion in a porous layer saturated by a viscous fluid is considered numerically. The impact of vertical throughflow on stability is also studied. Linear, quadratic, cubic and exponential functions are taken into consideration for gravity force variation. To solve the eigenvalue problem numerically, bvp4c method has been employed. The results show that Lewis number, gravity variation parameter, and Soret parameter are delaying the onset of convection, while solutal Rayleigh number and viscous dissipation parameter are enhancing the onset of convection in the flow field. It is distinguished that the system is becoming more stable for the exponential variation of the gravity field and more unstable for cubic variation of gravity variation. [ABSTRACT FROM AUTHOR]

In this work, an attempt has been made to develop thin and flexible transparent conductors based on the interfaces of Ag nanoparticles (AgNP) and Al:ZnO (AZO) deposited by sequential magnetron sputtering. The entire deposition process is completed within 20–28 min without breaking vacuum thereby preventing post-deposition oxidation of Ag NPs. The co-existence of high transmittance and low sheet resistance along with stability under mechanical bending is a bit difficult to achieve in bare AZO thin film having thickness below 200 nm. The resistivity of the optimized AZO/AgNP/AZO composite structure is significantly low at 3.3 × 10−5 Ω cm, which is two orders lower than that of AZO thin film of similar thickness. The figure of merit of the optimized composite structure peaks at 39.0 mΩ−1 corresponding to Ag NPs growth period of 5 min. The novel fabrication of AZO/AgNP interface in a dry and vacuum environment facilitates superior bending stability required for a flexible transparent conductor. The findings suggest that a system of two thin layers of AZO with embedded Ag NPs can be a potential candidate as an indium free transparent conductor for the next generation optoelectronic device. • Al:ZnO (AZO) and Ag nanoparticles (AgNP) based composite transparent conductor. • Flexible and thin AZO/AgNP/AZO composite prepared by magnetron sputtering. • Low sheet resistance of 2.3 Ω/□ with optimal figure of merit of 39.0 mΩ−1. • Marked reduction of resistivity of AZO due to embedded Ag nanoparticles. • Bending stability due to effective AZO/AgNP interface prepared in vacuum environment. [ABSTRACT FROM AUTHOR]