Effect of CuO-, SiO2-, and Al2O3-based nanofluids on automotive cooling systems from laminar to turbulent flow regime—A CFD study

In recent studies, much attention has been given to nanofluids suggesting that adding nanoparticles in base fluids offers a higher heat transfer rate compared with conventional fluids. This study is based on the numerical investigation of different types of nanofluids, consisting of CuO (50 nm), SiO₂ (40 nm), and Al₂O₃ (15 nm) nanoparticles at different volume concentrations. Several simulations were performed from low to high Reynolds numbers, corresponding to laminar and turbulent flow regimes using ANSYS-Fluent CFD solver. Results suggest that under a laminar flow regime with the same Reynolds number of 2000, CuO-based nanofluids perform better as compared with SiO₂ and Al₂O₃-based nanofluids with Nusselt number (Nu) having percentage increase of 90% and 60% comparing with SiO₂- and Al₂O₃-based nanofluids, respectively. However, at higher Reynolds numbers when the flow is turbulent, Al₂O₃-based nanofluids demonstrate better performance having a percentage increase in Nusselt numbers equal to 40% and 23% as compared with CuO and SiO₂-based nanofluids respectively under the same Reynolds number of 15,000. This implies that turbulence has a significant effect on heat transfer rate, and is not only related to thermal conductivity. This study will help in designing more compact cooling systems for engines and the internal environment of motor vehicles.     

The Impact of Nonthermal Technologies on the Microbiological Quality of Juices: A Review

Fruit and vegetable juices are rich sources of nutrients that support microbiological growth and ultimately undergo rapid deterioration of safety and quality. The loss of nutritional quality of juices due to intensive thermal processing is a major problem encountered during the treatment of commercially preserved liquid foods. Conventional thermal processing technologies inactivate microorganisms and enzymes and extend the shelf life of foods but exert negative effects on nutritional and organoleptic properties of juices, for example, a loss of vitamins, of a desirable flavor, and of bioactive compounds and development of different sensory profiles as a result of heating. Nonthermal technologies including ultrasonication, a pulsed electric field, high‐pressure processing, irradiation, and their combinations are suitable alternatives for achieving the same preservation effect without the adverse effects of heat on the quality of juices and meet consumer demand for clean‐label, safe, and wholesome products without compromising their nutritional properties.     

Risk-free WHO grading of astrocytoma using convolutional neural networks from MRI images

Multimedia Tools and Applications - Astrocytoma is the most common and aggressive brain tumor, in its highest grade, the prognosis is ‘low survival rate’. Spinal tap and biopsy are the...     

A new parameter and its effect on the formability in single point incremental forming: A fundamental investigation

A new parameter, blank stiffness, with a potential effect on the formability in single point incremental forming (SPIF) has been introduced and investigated. Various plates with a square hole at the center and half-side length of the square ranging from 12–56mm were used as backing plates for blanks. It is shown that with a decrease in the size of hole/work-piece, there is an increase in the blank stiffness. This increase in the stiffness in turn adversely affects the formability in SPIF process.     

A note on proper curvature collineations in Bianchi type VIII and IX space-times

We investigate proper curvature collineations in Bianchi type VIII and IX space-times using the rank of the 6 x 6 Riemann matrix and direct integration techniques. We found only one case when the above space-times become static and admit proper curvature collineations which form an infinite-dimensional vector space.     

Binary phase solid‐state photopolymerization behavior of acrylate cryogels under different light sources

Two types of cryogels were obtained using 2‐hydroxyethyl acrylate (HEA) and 2‐hydroxyethyl methacrylate (HEMA) by homogeneous mixing with poly(ethylene glycol) diacrylate (PEGDA) as crosslinker at subzero temperature followed by photopolymerization with two different light initiation sources (high‐pressure Hg arc lamp and UV‐LED).The solution was frozen unidirectionally at ?60 °C before polymerization and finally photopolymerized at the same temperature. The cryogels were characterized using photo‐DSC, UV–vis and Fourier transform infrared spectroscopy, and scanning electron microscopy techniques. The cryogels cured with an LED light showed a higher polymerization rate and better morphological characteristics than ones cured with a high‐pressure Hg arc. The water intake ratio of HEA/PEGDA was higher than HEMA/PEGDA for both curing sources. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46686.     

Physicochemical properties of aqueous solutions of sodium glycinate in the non-precipitation regime from 298.15 to 343.15 K

The physicochemical properties, including the density, viscosity, and refractive index of aqueous solutions of sodium glycinate as a solvent for CO2 absorption in the non-precipitation regime were measured under the wide temperature range of 298.15 to 343.15 K. The concentration of the sodium glycinate in an aqueous form in the non-precipitation regime was identified up to 2.0 mol·L?1. The coefficients of thermal expansion values were estimated from measured density data. It was found that, the densities, viscosities and refractive indices of the aqueous sodium glycinate decrease with an increase in temperature, whereas with increasing sodium glycinate concentration in the solution, all three properties increase. Thermal expansion coefficients slightly increase with rising temperature and concentration. The measured values of density, viscosity and refractive index were correlated as a function of temperature by using the least squares method. The predicted data obtained from correlation equations for all measured properties were in fairly good agreement with the experimental data.     

Melting behavior and superheating capacity of REBa2Cu3Oy films with nano‐layer buffered structures

Using high temperature‐optical microscopy, in situ investigations were conducted on melting and superheating behaviors of REBa₂Cu₃O_7?δ (RE123, RE = Nd, Gd) films, which were grown on nano‐layer buffered substrates. The results demonstrate that all buffered RE123 films have improved crystallinity and in‐plane alignments, leading to the higher superheating capability. In the first case, due to its good lattice match with the buffer material of Y123, the Nd123 film with the minimal extrinsic property grew from the superior interface. In the second circumstance, because of its stronger chemical bonding with the buffer layer of Gd₂O₃, the pure c‐axis oriented Gd123 film was fabricated. Moreover, the optimized thickness of buffer layer plays an important role in reducing interface energy of RE123 films and enhancing its superheating capacity.     

The role of graphene and europium on TiO2 performance for photocatalytic hydrogen evolution

Highly efficient Eu-TiO₂/graphene composites were synthesized by a two-step method such as sol-gel and hydrothermal process. The synthesized photocatalysts were characterized by XRD, TEM, XPS, UV–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The results confirmed that anatase Eu-TiO₂ nanoparticles with average 10 nm sizes were successfully deposited on two-dimensional graphene sheets. The UV–visible spectroscopy showed a red shift in the absorption edge of TiO₂ due to Eu doping and graphene incorporation. Moreover, effective charge separation in Eu-TiO₂/graphene composites was confirmed by PL emission spectroscopy compared to TiO₂/graphene, Eu-TiO₂ and pure TiO₂. The photocatalytic activity for H₂ evolution over prepared composites was studied under visible light irradiation (λ ≥ 400 nm). The results demonstrate that photocatalytic performance of the photocatalysts for hydrogen production increases with increasing doping concentration of Eu upto 2 at%. However, further increase in doping content above this optimum level has decreased the performance of photocatalyst. The enhanced photocatalytic performance for H₂ evolution is attributed to extended visible light absorption, suppressed recombination of electron-hole pairs due to synergistic effects of Eu and graphene.     

Dynamic Response in Ba1−xSrxTiO3 and Anomalous Behavior at the Phase Boundary Composition

The dynamic response of Barium Strontium Titanate (Ba_1?xSr_xTiO₃, x = 0.6–0.9) is presented over a temperature range spanning various structural phase transitions and for compositions that extend from the ferroelectric (FE) phase to the FE‐Antiferrodistortive (AFD) phase boundary. We find that while the in‐phase part of the dielectric response is insensitive to applied frequencies over the range 400–500 kHz for all compositions, strong dispersive effects are observed in general for the out of phase part, for almost all compositions. The dielectric peaks corresponding to the lower temperature structural transitions (e.g. tetragonal to orthorhombic T–O etc.) exhibit frequency dependence, while the higher temperature cubic to tetragonal (C–T) transition does not show dispersive effects. The only exception to this is for the Ba_0.1Sr_0.9TiO₃ composition, lying at the boundary of the FE and AFD phases. Detailed frequency dependence studies of this composition (x = 0.9) show that the (C–T) transition exhibits an abrupt change in the dispersive features for high frequencies f > 10 kHz. These features include the constancy of peak temperature, large drop in the magnitude of the losses and a noticeable broadening of the associated loss peak. The anomalous features in the behavior of x = 0.9 composition are attributed to slow relaxation processes in the AFD phase at the boundary separating the FE and AFD phases.