Zinc oxide–silver/water hybrid nanofluid flow toward an off-centered rotating disk using temperature-dependent experimental-based thermal conductivity

Herein, the off-centered stagnation flow and heat transfer of zinc oxide–silver/water hybrid nanofluid over a rotating disk according to the mass-based algorithm is studied. It is assumed that the nanoparticles have a spherical shape. Also, the velocity slip between the base fluid and nanoparticles is negligible. The Prandtl number is kept constant at 6.2. In addition, it has been used an experimental relation for effective thermal conductivity which is a function of volume fraction and temperature. The governing partial differential equations are converted to dimensionless ordinary differential equation (ODE)s by the similarity transformation method. The simplified ODEs are solved numerically by the bvp4c function from MATLAB which is an efficient and reliable code according to the three-stage Lobatto IIIa formula. The influence of rotational parameters and both nanoparticles masses on the profiles and quantities of engineering interest are presented and discussed in detail. It is shown that the flow becomes complicated when there is a distance between the flow axis and the disk axis. Under determined conditions for a hybrid nanofluid with 30-g mass for both nanoparticles and 100-g mass for pure water, adding 30 g of the second nanoparticle's mass into the base fluid leads to enhance all hydrodynamic quantities of engineering interest by about 4.3%, while dispersing 30 g of the first nanoparticle's mass inside water results in decreasing the similarity temperature gradient at the surface about 3.6%. Also, when the disk rotates faster, the maximum radial velocity near the disk, s′(0) and f″(0) increases.     

Image classification based on sparse-coded features using sparse coding technique for aerial imagery: a hybrid dictionary approach

Neural Computing and Applications - This work offers an approach to aerial image classification for use in remote sensing object recognition, image processing and computer vision. Sparse coding...     

Effect of Wettability Enhancement of SiC Particles on Impact Toughness and Dry Sliding Wear Behavior of Compocasted A356/20SiCp Composites

In this study, the effect of wettability improvement of SiCp on the impact and sliding wear behavior of A356/20 wt% SiCp composites produced by a compocasting technique has been investigated. The result showed an increase of incorporation and uniform distribution of SiCp in the A356 matrix by elimination of SiCp segregation. Desired bonding between SiCp and the aluminum matrix due to improved wettability resulted in enhanced properties in terms of improved impact toughness and wear resistance. This improvement was also associated with partial refinement of coarse eutectic silicon due to increased incorporation and distribution of SiCp reinforcements. The highest enhancement was obtained when 1% Mg was added into the melt in addition to pretreated SiCp. The impact toughness value increased by 10 and 26% and the wear rate decreased by 5 and 30% when the SiC was treated and when Mg was added, respectively, compared to as-received SiCp. The impact fracture surfaces showed fewer decohered and well-bonded SiC particles in A356–(SiC-treated-Mg) composite. The highest wear resistance of A356/SiCp composites was achieved by A356–(SiC-treated-Mg) composite for applied loads of 10 and 20 N compared to other fabricated composites. The worn surface revealed mild abrasion and adhesion wear mechanisms.     

HOOSC: heterogeneous online/offline signcryption for the Internet of Things

Wireless Networks - In order to improve the accessibility of the services provided by a sensor network, wireless sensor networks (WSNs) is integrated to Internet of Things (IoTs). In this case, the...     

Kinetic simulation of flameless burners with methane/hydrogen blended fuel: Effects of molecular diffusion and Schmidt number

The newly developed concept of MILD combustion has paved the way through achievement of high thermal efficiencies with low levels of pollutants and greenhouse gases. High fidelity numerical models play key role in design and optimization of these burners. The present research aims to assess the effect of molecular diffusion and deviations in the amount of different species Schmidt number on the precision of the model. To this end, a previously investigated MILD burner is opted as case-study. From the results it is evident that in contrast to conventional combustion regimes problems, the impact of the often-neglected laminar diffusion is comparable to turbulent diffusion. On the other hand, consideration of molecular diffusion in the species transport equation significantly improves the model accuracy only if proper Schmidt number for species are considered. Suitable Sutherland coefficients and Schmidt numbers for each species are found based on relevant data in the literature and reported.     

Selective Bragg reflection of visible light from coaxial electrospun fiber mats

Electrospinning is a relatively unsophisticated technique for generating continuous fibers whose diameters can approach nanoscale dimensions. In coaxial electrospinning, two different liquids can be spun, one inside the other, to produce a composite fiber with a core-sheath structure. We prepared dual-core fibers consisting of poly vinyl-pyrrolidone sheaths and cores of the short-pitched chiral nematic mixture CB15:E9. The flow rates, polymer concentration, and applied voltage were optimized prior to fiber production. The fibers were deposited as uniform nonwoven mats that displayed selective reflection of visible light from the blue phase of the confined chiral liquid crystal. These reflections are both temperature dependent and reversible and such mats offer potential as flexible sensors.     

Sensitivity analysis of fission product activity in primary coolant of typical PWRs

A model has been developed for static and dynamic activity analysis of the fission product activity (FPA) in primary coolant of typical pressurized water reactors (PWRs). It has been implemented in the FPCART based computer program FPCART-SA. For long steady power operation of reactor, the computed values of normalized static sensitivity have been compared with the corresponding values obtained by using the dynamic sensitivity analysis. The normalized sensitivity values for the reactor power (P), failed fuel fraction (D), coolant leakage rate (L), total mass of coolant (m) and the let-down flow rate (Q) have been calculated and the values: 1.0, 0.857, −2.0177 × 10⁻⁶, 2.349 × 10⁻⁴, −2.329 × 10⁻⁴ have been found correspondingly for Kr-88 with the dominant value of FPA as 0.273 μCi/g.