Prediction of hydrothermal behavior of a non-Newtonian nanofluid in a square channel by modeling of thermophysical properties using neural network

Journal of Thermal Analysis and Calorimetry - This paper assesses the contribution of TiO2 nanoparticles on thermal performance of a 0.5 mass% aqueous solution of carboxymethyl cellulose...     

The Solution of Tachyon Inflation in Curved Universe

In this paper, we have considered the curved universe which is filled by tachyonic field. We have found the exact solutions for the field, pressure, density, and scale factor and some cosmological parameters. In such universe, we have investigated the role of tachyonic field in different stages of k for the evolution of the universe. Finally we draw the graphs for the scale factor, Hubble’s parameter, energy density, pressure, acceleration parameter, equation of state and potential for the different values of k. Also we obtained the exact form of field which shows that the tachyonic field has the kink form.     

Synthesis,spectroscopic characterization,crystal structure and thermal analyses of two zinc(II) complexes with methanolysis of 2-pyridinecarbonitrile as a chelating ligand

Zinc(II) complexes, [Zn(MPCA)₃][ZnCl₄] (1) and [Zn(MPCA)₃][ZnBr₄] (2) (where MPCA is O-methylpyridine-2-carboximidate), were synthesized from the reaction of ZnCl₂ and ZnBr₂ with 2-pyridinecarbonitrile in methanol, respectively. Both complexes were thoroughly characterized by elemental analysis, thermogravimetric analysis, differential thermal analysis and IR, UV–Vis, ¹H NMR spectroscopy, and their structures have been determined by the single-crystal X-ray diffraction. The spectroscopic investigations and X-ray structural analysis indicated that in both complexes, the nitrile group of ligand has been methoximation in methanol solvent in the presence of zinc(II) salts. The luminescence spectra of both complexes show that the intensity of their emission bands is stronger than that of the bands for the free O-methylpyridine-2-carboximidate ligands.     

Experimental study on convective heat transfer and entropy generation of carbon black nanofluid turbulent flow in a helical coiled heat exchanger

Journal of Thermal Analysis and Calorimetry - The convective heat transfer coefficient (CHTC) of a fluid is one of the most effective factors on the performance of a fluid in heat transfer...     

A new acylated flavonoid tetraglycoside with anti-inflammatory activity from Tipuana tipu leaves

A new acylated kaempferol glycoside, kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-O-[β-d-glucopyranosyl-(1 → 2)-4-O-acetyl-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranoside, has been isolated from the leaves of Tipuana tipu (Benth.) Lillo growing in Egypt, along with three known flavonol glycosides, kaempferol 3-O-rutinoside, quercetin 3-O-rutinoside (rutin) and kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 6)]-[α-l-rhamnopyranosyl-(1 → 2]-β-d-glucopyranoside. Structure elucidation was achieved through different spectroscopic methods. Structure relationship with anti-inflammatory activity using carrageenin-induced rat paw oedema model is discussed.     

Development of Ferromagnetic Materials Containing Co2P,Fe2P Phases from Organometallic Dendrimers Precursors

The development of synthesis methods to access advanced materials, such as magnetic materials that combine multimetallic phosphide phases, remains a worthy research challenge. The most widely used strategies for the synthesis of magnetic transition metal phosphides (TMPs) are organometallic approaches. In this study, Fe-containing homometallic dendrimers and Fe/Co-containing heterometallic dendrimers were used to synthesize magnetic materials containing multimetallic phosphide phases. The crystalline nature of the nearly aggregated particles was indicated for both designed magnetic samples. In contrast to heterometallic samples, homometallic samples showed dendritic effects on their magnetic properties. Specifically, saturation magnetization (M_s) and coercivity (H_c) decrease as dendritic generation increases. Incorporating cobalt into the homometallic dendrimers to prepare the heterometallic dendrimers markedly increases the magnetic properties of the magnetic materials from 60 to 75 emu/g. Ferromagnetism in homometallic and heterometallic particles shows different responses to temperature changes. For example, heterometallic samples were less sensitive to temperature changes due to the presence of Co₂P in contrast to the homometallic ones, which show an abrupt change in their slopes at a temperature close to 209 K, which appears to be related to the Fe₂P ratios. This study presents dendrimers as a new type of precursor for the assembly of magnetic materials containing a mixture of iron- and cobalt-phosphides phases with tunable magnetism, and provides an opportunity to understand magnetism in such materials.     

Highly Sensitive Impedimetric Biosensor Based on Thermolysin Immobilized on a GCE Modified with AuNP-decorated Graphene for the Detection of Ochratoxin A

The fabrication of a thermolysin-based biosensor capable of detecting ochratoxin A (OTA) from food samples is described. The electrochemical deposition of calcium cross-linked cellulose film (CCLC) and gold nanoparticles (AuNPs) on graphene (GR) for modification of a glassy carbon electrode (GCE) is the first step. Then the thermolysin (TLN) enzyme in a polyvinyl alcohol (PVA)/polyethylenimine (PEI) matrix is immobilized. The impedimetric biosensor response is linear from 0.2 nM to 100 nM with a detection limit of 0.2 nM. The obtained stable and reproducible biosensor is then applied for the detection of OTA in spiked extracts from coffee beans.     

Assessing the Efficiency of Sodium Ferrate Production by Solution Plasma Process

Plasma Chemistry and Plasma Processing - Application of sodium ferrate (Na2FeO4) is considered as the environmental friendly and cost-effective method for oxidation, coagulation and disinfection...     

Ultrasound promoted rapid and green synthesis of 1,8-dioxo-octahydroxanthenes derivatives using nanosized MCM-41-SO3H as a nanoreactor,nanocatalyst in aqueous media

An efficient and green procedure has been developed for the synthesis of 1,8-dioxo-octahydroxanthenes derivatives. The reaction was carried out in water under ultrasound irradiation, using nanosized MCM-41-SO₃H. In this method, several types of aromatic aldehyde, containing electron-withdrawing groups as well as electron-donating groups, were rapidly converted to the corresponding 1,8-dioxo-octahydroxanthenes in good to excellent yields. This novel synthetic method is especially favored because it provides a synergy of the nanosized MCM-41-SO₃H and ultrasound irradiation which offers the advantages of high yields, short reaction times, simplicity and easy workup compared to the conventional methods reported in the literature.     

Simulation of nonlinear fractional dynamics arising in the modeling of cognitive decision making using a new fractional neural network

By the rapid growth of available data, providing data-driven solutions for nonlinear (fractional) dynamical systems becomes more important than before. In this paper, a new fractional neural network model that uses fractional order of Jacobi functions as its activation functions for one of the hidden layers is proposed to approximate the solution of fractional differential equations and fractional partial differential equations arising from mathematical modeling of cognitive-decision-making processes and several other scientific subjects. This neural network uses roots of Jacobi polynomials as the training dataset, and the Levenberg-Marquardt algorithm is chosen as the optimizer. The linear and nonlinear fractional dynamics are considered as test examples showing the effectiveness and applicability of the proposed neural network. The numerical results are compared with the obtained results of some other networks and numerical approaches such as meshless methods. Numerical experiments are presented confirming that the proposed model is accurate, fast, and feasible.