Performance investigation on fin type solar still with paraffin wax as energy storage media

Journal of Thermal Analysis and Calorimetry - It is indispensable to enhance the performance of a conventional solar still in order to increase its productivity. It has been effectively done by...     

A Proficient approach to enhance heat transfer using cupric oxide/silica hybrid nanoliquids

Journal of Thermal Analysis and Calorimetry - High performance cooling anticipated in smaller size heat transfer equipment is the most significant challenge in many industries including CPU...     

Crystal structural, magnetic, and transport properties of layered cobalt oxyfluorides, Sr2CoO(3+x)F(1-x) (0 ≤ x ≤ 0.15)

The crystal structure of the layered cobalt oxyfluoride Sr(2)CoO(3)F synthesized under high-pressure and high-temperature conditions has been determined from neutron powder diffraction and synchrotron powder diffraction data collected at temperatures ranging from 320 to 3 K. This material adopts the tetragonal space group I4/mmm over the measured temperature range and the crystal structure is analogous to n = 1 Ruddlesden-Popper type layered perovskite. In contrast to related oxyhalide compounds, the present material exhibits the unique coordination environment around the Co metal center: coexistence of square pyramidal coordination around Co and anion disorder between O and F at the apical sites. Magnetic susceptibility and electrical resistivity measurements reveal that Sr(2)CoO(3)F is an antiferromagnetic insulator with the Néel temperature T(N) = 323(2) K. The magnetic structure that has been determined by neutron diffraction adopts a G-type antiferromagnetic order with the propagation vector k = (1/2 1/2 0) with an ordered cobalt moment μ = 3.18(5) μ(B) at 3 K, consistent with the high spin electron configuration for the Co(3+) ions. The antiferromagnetic and electrically insulating states remain robust even against 15%-O substation for F at the apical sites. However, applying pressure exhibits the onset of the metallic state, probably coming from change in the electronic state of square-pyramidal coordinated cobalt.     

Nanocrystalline tin compounds/graphene nanocomposite electrodes as anode for lithium-ion battery

Nanocrystalline tin (Sn) compounds such as SnO₂, SnS₂, SnS, and graphene nanocomposites were prepared using hydrothermal method. The X-ray diffraction (XRD) pattern of the prepared nanocomposite reveals the presence of tetragonal SnO₂, hexagonal SnS₂, and orthorhombic SnS crystalline structure in the SnO₂/graphene nanosheets (GNS), SnS₂/GNS, and SnS/GNS nanocomposites, respectively. Raman spectroscopic studies of the nanocomposites confirm the existence of graphene in the nanocomposites. The transmission electron microscopy (TEM) images of the nanocomposites revealed the formation of homogeneous nanocrystalline SnO₂, SnS_2, and SnS particle. The weight ratio of graphene and Sn compound in the nanocomposite was estimated using thermogravimetric (TG) analysis. The cyclic voltammetry experiment shows the irreversible formation of Li₂O and Li₂S, and reversible lithium-ion (Li-ion) storage in Sn and GNS. The charge–discharge profile of the nanocomposite electrodes indicates the high capacity for the Li-ion storage, and the cycling study indicates the fast capacity fading due to the poor electrical conductivity of the nanocomposite electrodes. Hence, the ratio of Sn compounds (SnO₂) and GNS have been altered. Among the examined SnO₂:GNS nanocomposites ratios (35:65, 50:50, and 80:20), the nanocomposite 50:50wt% shows high Li-ion storage capacity (400 mAh/g after 25 cycles) and good cyclability. Thus, it is necessary to modify GNS and Sn compound composition in the nanocomposite to achieve good cyclability.     

Particles dispersion on fluid-liquid interfaces

This paper is concerned with the dispersion of particles on the fluid-liquid interface. In a previous study we have shown that when small particles, e.g., flour, pollen, glass beads, etc., contact an air-liquid interface, they disperse rapidly as if they were in an explosion. The rapid dispersion is due to the fact that the capillary force pulls particles into the interface causing them to accelerate to a large velocity. In this paper we show that motion of particles normal to the interface is inertia domin...     

Adsorption of fatty acids on iron (hydr)oxides from aqueous solutions

The interaction of iron (hydr)oxides with fatty acids is related to many industrial and natural processes. To resolve current controversies about the adsorption configurations of fatty acids and the conditions of the maximum hydrophobicity of the minerals, we perform a detailed study of the adsorption of sodium laurate (dodecanoate) on 150 nm hematite (α-Fe(2)O(3)) particles as a model system. The methods used include in situ FTIR spectroscopy, ex situ X-ray photoelectron spectroscopy (XPS), measurements of the adsorption isotherm and contact angle, as well as the density functional theory (DFT) calculations. We found that the laurate adlayer is present as a mixture of inner-sphere monodentate mononuclear (ISMM) and outer-sphere (OS) hydration shared complexes independent of the solution pH. Protonation of the OS complexes does not influence the conformational order of the surfactant tails. One monolayer, which is filled through the growth of domains and is reached at the micellization/precipitation edge of laurate, makes the particles superhydrophobic. These results contradict previous models of the fatty acid adsorption and suggest new interpretation of literature data. Finally, we discovered that the fractions of both the OS laurate and its molecular form increase in D(2)O, which can be used for interpreting complex spectra. We discuss shortcomings of vibrational spectroscopy in determining the interfacial coordination of carboxylate groups. This work advances the current understanding of the oxide-carboxylate interactions and the research toward improving performance of fatty acids as surfactants, dispersants, lubricants, and anticorrosion reagents.