Effect of Newtonian heating/cooling on free convection in an annular permeable region in the presence of heat source/sink

The influence of Newtonian heating/cooling in the presence of heat source/sink has been investigated on laminar free convective flow in a vertical annular permeable region. The mathematical model for the problem has been considered as a boundary value problem consisting of two simultaneous ordinary differential equations. The boundary value problem has been transformed to nondimensional form. This has given rise to a number of parameters representing both geometrical and physical features of the problem. Closed‐form analytical solutions of the governing equations have been obtained for two different cases of internal heat generation/absorption. To assess the effects of governing parameters on the fluid velocity and temperature, a number of profiles of these field variables have been presented. The efficacy of the distinct processes on the field variables has been discussed extensively. The main outcome obtained in this study is that the velocity as well as temperature is enhanced in the case of the Newtonian heating while the opposite behavior occurs in the Newtonian cooling for both cases of source and sink. Furthermore, the influence of the governing parameters has been shown on the skin friction, volume flow rate, and the Nusselt number.     

Analysis and assessment of a nanoparticle seeded small scale absorption refrigeration system driven by a low‐grade waste heat source

The thermoeconomic behaviour of a nanoparticle seeded single effect LiBr‐H₂O absorption refrigeration system (ARS) is investigated for a small scale application. In the proposed method, alumina nanoparticles with volume concentrations of 3%, 5%, and 7% are dispersed into an aqua lithium bromide solution. The multiobjective heat transfer search algorithm is employed to examine the design trade‐off between the coefficient of performance (COP) and total annualized cost (TAC). To analyze the overall performance of the system, the influence of five design parameters, namely the temperatures of the generator, absorber, evaporator, condenser and heat exchanger pipe diameter, are studied. It is found that with an increase in the COP, the TAC of the system is initially raised marginally, and after that, raised rigorously with further increment. The comparative results indicate that the COP and TAC of the nanofluid based ARS system are increased by about 7% and decreased by about 3.2%, respectively, corresponding to the Pareto points of the base ARS system. A lower break‐even point of about 2.6 years is achieved for the ARS system containing nanoparticles compared to the base ARS system. Overall, the ARS system containing 5% nanoparticles is the best solution from a thermodynamic and economic point of view.     

A multi-tier based clustering framework for scalable and energy efficient WSN-assisted IoT network

Wireless Networks - The effectiveness of wireless sensor network (WSN) in Internet of Thing (IoT) based large scale application depends on the deployment method along with the routing protocol. The...     

Distribution and Prediction of Boundary Shear in Diverging Compound Channels

Measurement of bed shear stress is always a challenging task for engineers. In river engineering, bed shear is a fundamental variable and is important in estimating flow resistance and sediment transport. In this study, experiments are carried out in diverging compound channel with smooth bed (perspex sheet) and rough bed (Gravel) conditions to determine the effect of roughness. The shear velocity is estimated from universal logarithmic law. The effect of geometry and roughness on Von-Karman constant, eddy viscosity coefficient, friction factor is studied. The mass conservation and momentum conservation equations are used to derive apparent shear forces at interface of main channel and floodplain. A genetic algorithm model is developed to predict percentage of shear force (%Sfp) carried by sub-sections. To perform better with less and unseen data K-Fold cross-validation technique is used. The model is compared with available models in literature and it is observed that developed model gave better predictions with low MAPE.

     

Influence of Al doping in LaCoO3 on structural,electrical and magnetic properties

We report investigations on polycrystalline LaCo_1?x Al _x O₃ (x = 0–0.9) bulk samples. The solid state synthesized samples showed a coexistence of rhombohedral and monoclinic phases in the intermediate concentrations (0.2 ≤ x ≤ 0.5) and pure rhombohedral phase otherwise. The observed effect of Al doping on dc transport has been analysed on the basis of small polaron hopping mechanism. The magnetisation results presented give evidence of weak ferromagnetism and anomalous temperature dependence of coercivity which we associate to the canting of the localised high-spin Co(III) and anti-symmetric exchange interactions at low temperatures.     

Effect of hydrophilic and hydrophobic polymers on permeation of S-amlodipine besylate through intercalated polymeric transdermal matrix: 3(2) designing,optimization and characterization

Objective: Innovation in material science has made it possible to fabricate a pharmaceutical material of modifiable characteristics and utility, in delivering therapeutics at a sustained/controlled rate. The objective of this study is to design and optimize the controlled release transdermal films of S-Amlodipine besylate by intercalating hydrophilic and hydrophobic polymers.

Methods: 3(2) factorial design and response surface methodology was utilized to prepare formulations by intercalating the varied concentration of polymers(A) and penetration enhancer(B) in solvent. The effect of these independent factors on drug release and flux was investigated to substantiate the ex-vivo, stability and histological findings of the study.

Results: FTIR, DSC revealed the compatibility of drug with polymers; however, the semicrystallinity in drug was observed under PXRD. SEM micrographs showed homogeneous dispersion and entanglement of drug throughout the matrix. Results from the permeation study suggested the significant effect of factors on the ex vivo permeation of drug. It was observed that drug release was found to be increased with an increase in hydrophilic polymer concentration and PE. The formulations having polymers (EC:PVPK-30) at 7:3 showed maximum drug release with highest flux (102.60?±?1.12?µg/cm²/h) and permeability coefficient (32.78?±?1.38?cm/h). Significant effect of PE on lipid and protein framework of the skin was also observed which is responsible for increased permeation. The optimized formulation was found to be stable and showed no-sign of localized reactions, indicating safety and compatibility with the skin.

Conclusion: Thus, results indicated that the prepared intercalated transdermal matrix can be a promising nonoral carrier to deliver effective amounts of drug.     

Covalent functionalization of zinc oxide nanowires for high sensitivity p-nitrophenol detection in biological systems

High-quality zinc oxide (ZnO) nanowires were synthesized using the atmospheric chemical vapor deposition technique and were appropriately characterized. Subsequently, the nanowire surface was covalently grafted with 1-pyrenebutyric acid (PBA) fluorophore, and surface-sensitive X-ray photoelectron spectroscopy and Fourier transform infrared-attenuated total reflectance spectroscopy were utilized to confirm the functionalization of 1-pyrenebutyric acid on the nanowire surface. Additionally, photoluminescence (PL) measurements were used to evaluate the optical behavior of pristine nanowires. Through fluorescence quenching of 1-pyrenebutyric acid by p-nitrophenol, a detection limit of 28 ppb was estimated. Based on these findings, ZnO nanowires functionalized with 1-pyrenebutyric acid are envisaged as extremely sensitive platforms for the ultra-trace detection of p-nitrophenol in biological systems.     

Direct three dimensional tomography of flames using maximization of entropy technique

Presently, there are numerous applications for non-destructive techniques like emission tomography, laser based methods and particle image velocimetry that are used to study flame characteristics. Reconstruction of the flame intensity field using emission tomography has the advantage over other technologies that it gives accurate results but at the same time requires relatively inexpensive equipment, and therefore, has numerous industrial applications. In the present paper, a new algorithm performing Direct-3D reconstruction using the maximization of entropy (MENT) methodology has been introduced. Through detailed studies using a mathematical object, it has been shown that the Direct-3D algorithm shows significantly reduced errors as compared to 2D slice-by-slice reconstruction algorithms. Secondly, the major features of the proposed algorithm, for e.g., effect of orientation, effect of number of views, and robustness have been discussed. Finally, a few qualitative results from actual flames have been presented using a candle and a gas fired burner, and the results match well with the actual flame geometry and intensity distribution.