Effect of electromagnetic field on the thermal performance of longitudinal trapezoidal porous fin using DTM–Pade approximant

The heat transfer and thermal distribution through porous fins have gotten a lot of attention in recent years due to their extensive applications in the manufacturing and engineering field. In porous fins, the impact of magnetic field aids in improved heat transfer enhancement. Also, the combination of an electric effect and a magnetic field considerably enhances heat transfer. In this direction, the thermal distribution through a convective–radiative longitudinal trapezoidal porous fin with the impact of an internal heat source and an electromagnetic field is discussed in the present analysis. The governing heat equation is nondimensionalized with nondimensional terms, and the transformed nonlinear ordinary differential equation is solved analytically using the DTM–Pade approximant algorithm. Furthermore, the graphical discussion is presented to explore the impact of various nondimensional parameters, such as convection-conduction parameter, fin taper ratio, thermomagnetic field, radiation–conduction parameter, internal heat generation parameter, and thermoelectrical field on the temperature gradient of the fin. The investigation's key findings disclose that as the magnitude of the convection–conduction parameter, fin taper ratio, and radiation–conduction parameter increase, the thermal distribution through the fin reduces. The thermal distribution inside the fin increases for the heat-generating parameter, thermoelectric, and thermomagnetic fields.     

Development and Control of Bacterial Biofilms on Dairy Processing Membranes

Membrane fouling is a major operational problem that leads to reduced membrane performance and premature replacement of membranes. Bacterial biofilms developed on reverse osmosis membranes can cause severe flux declines during whey processing. Various types of biological, physical, and chemical factors regulate the formation of biofilms. Extracellular polymeric substances produced by constitutive microflora provide an effective barrier for the embedded cells. Cultural and microscopic techniques also revealed the presence of biofilms with attached bacterial cells on membrane surfaces. Presence of biofilms, despite regular cleaning processes, reflects ineffectiveness of cleaning agents. Cleaning efficiency depends upon factors such as pH of the cleaning agent, temperature, pressure, cleaning agent dose, optimum cleaning time, and cross‐flow velocity during cleaning. Among different cleaning agents, surfactants help to prevent bacterial attachment to surfaces by reducing the surface tension of water and interfacial tension between the layers. Enzymes mixed with surfactants and chelating agents can be used to penetrate the biofilm matrix formed by microbes. Recent studies have shown the role of quorum‐sensing‐based cell‐to‐cell signaling, which provides communication within bacterial cells to form a mature biofilm, and also the role of applying quorum inhibitors to prevent biofilm formation. Major cleaning applications are also summarized in Table 1 .     

Analysis of a fully wetted moving fin with temperature‐dependent internal heat generation using the finite element method

The temperature field of a moving longitudinal porous fin with varying internal heat generation with respect to temperature has been studied under natural radiation and convection effects. The Darcy model was implemented for the analysis and the parameters, whose effect on the thermal process were grouped and nondimensionalized. By using the finite element method, the obtained highly nonlinear second order ordinary differential equations were numerically solved. The relevant parameters were studied by means of graphs and subsequently their importance in the rate of heat transfer was interpreted.     

Nanowire-based electrochromic devices

This report presents studies performed on high contrast electrochromic devices based on WO₃ nanowires. The devices were made in two formats. The first kind was made with vertically oriented nanowires grown on fluorinated tin oxide (FTO) coated glass substrates using a low pressure hot filament CVD process. The devices made with these substrates showed a highly reversible transmission modulation of over 70% with almost 0% transmission in the colored state, at a wavelength of 700 nm. In the second kind of devices, made using dispersed nanowires in a mat-like format, a transmission modulation of over 50% was observed in the same wavelength regime. The bleaching times of electrodes with high densities of nanowire arrays showed a large dependence of bleaching timescales based on the coloration timescales used. Beyond the observed enhancement in the optical transmission contrast characteristics, the coloration and bleaching timescales can be further improved by optimizing the nanowire array characteristics such as their densities and aspect ratios.     

Symmetry and crystal structure of Ti3SiC2

Convergent beam electron diffraction (CBED) and X-ray diffractometry (XRD) have been used to examine the symmetry, structure and lattice parameters of Ti₃SiC₂. The CBED analysis confirms that the material is hexagonal with a point group of 6/mmm. The XRD diffraction peak positions and intensities are in good agreement with calculations based on previously proposed atomic positions.     

Toward high‐efficiency dye‐sensitized solar cells with a photoanode fabricated via a simple water‐based formulation

An aqueous formulation containing commercially available P25 nanoparticles and a water‐soluble precursor—titanium (IV) bis(ammonium lactato)dihydroxide (TALH) has been developed and optimized for fabricating photoanodes in dye‐sensitized solar cells. An optimal formulation achieved a power conversion efficiency of 9.2%. Solar cell performance is significantly influenced by precursor concentration impacting the porosity and electron transport of the thin film. The use of TALH during processing is shown to enhance the electron transport in the resulting titanium dioxide nanoparticle network using transient decay measurements. Bridging between neighboring nanoparticles is confirmed using transmission electron microscopy explaining the enhanced electron transport. The developed formulation has several advantages, as it is water‐based, composed of inexpensive, non‐hazardous components, is easy to make, and does not require special handling. The formulation has great potential for industrial applications, in particular for DSC manufacturing using roll‐to‐roll technology. Copyright © 2014 John Wiley & Sons, Ltd.     

Photoluminescence of GaN nanowires of different crystallographic orientations

We utilized time-integrated and time-resolved photoluminescence of a-axis and c-axis gallium nitride nanowires to elucidate the origin of the blue-shifted ultraviolet photoluminescence in a-axis GaN nanowires relative to c-axis GaN nanowires. We attribute this blue-shifted ultraviolet photoluminescence to emission from surface trap states as opposed to previously proposed causes such as strain effects or built-in polarization. These results demonstrate the importance of accounting for surface effects when considering ultraviolet optoelectronic devices based on GaN nanowires.     

Magnetohydrodynamic flow of Williamson fluid in a microchannel for both horizontal and inclined loci with wall shear properties

This study reports the flow of Williamson fluid in a microchannel, considering the effect of thermal radiation, heat source, slip regime, and convective boundary. The physical phenomenon is demonstrated by employing the Williamson model. The mathematical expressions are made dimensionless by using nondimensional quantities. The numerical approach called Runge–Kutta–Fehlberg scheme is hired to get the solution. The upshots of the pertinent flow parameter on physical features are visualized through graphs. It is established that the augmentation of Nusselt number has been achieved by increasing Weissenberg number and Reynolds number. In addition to this, it is emphasized that the reduction in the wall velocity gradient is obtained for a higher Weissenberg number.