Effect of polyethylenimine addition and washing on stability and electrophoretic deposition of Co3O4 nanoparticles

In this work, the parameters of cobalt oxide suspension such as conductivity, zeta potential, particle size, stability, and finally the electrophoretic behavior of particles in the absence and presence of polyethylenimine (PEI) in acetone medium were investigated. Also, the effects of washing on the stability and electrophoretic deposition of Co₃O₄ were studied. Characterization of the obtained layer by optical microscopy revealed that there was no deposition in the suspension without PEI, while a uniform layer was formed in the presence of PEI additive. Scanning electron microscopy (SEM) results confirmed the uniformity of layer obtained in acetone using PEI additive. Moreover, SEM results demonstrated that more porous microstructures were obtained at longer deposition durations. The difference in the porosity of the layers, as indicated by the SEM micrographs, is attributed to increase in the deposition time.     

Biodegradable polypropylene/thermoplastic starch nanocomposites incorporating halloysite nanotubes

In this work, polypropylene/thermoplastic starch (PP/TPS) with and without halloysite nanotubes (HNTs) was prepared via melt mixing in order to obtain environmentally friendly plastics. PP‐grafted maleic anhydride (PP‐g‐MA) was used to improve the compatibility among the highly incompatible polymers. The mechanical characterization showed a reduction in the tensile properties of the polymer when TPS increased; however, HNT successfully compensated for some of the observed losses. The results from the thermogravimetric analysis (TGA) indicated that HNT is an efficient reinforcement for the thermal stability improvement. TPS caused an increase in the storage modulus (G′) and the complex viscosity (η*) which marks a change in the viscoelastic properties of the system. The scanning electron microscope (SEM) images showed the effective plasticization of starch and better dispersion of TPS in the presence of HNT. Some samples were also buried in the soil to measure their sustainability after their lifetime lapse. The results indicated that TPS improves the biodegradability of the PP/TPS system. PP considerably lowered the moisture uptake of TPS; nevertheless, HNT caused a slight increase in the moisture absorption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45740.     

Sonochemical Synthesis and Characterization of A Nano-Rod Lead(II) Supramolecular, Three Dimensional Coordination Compound: New Precursor to Produce Pure Phase Nano-Sized Lead(II) Oxide

Nanorods of a lead(II) supramolecular three-dimensional (3D) coordination compound, [Pb(tfpb)₂]_n (1) (Htfpb?=?4,4,4-trifluoro-1-phenyl-1,3-butanedione), was prepared by the sonochemical method. The new nano-structure was characterized by scanning electron microscopy, X-ray powder diffraction, elemental analyses and IR spectroscopy. A single-crystal structure of the compound showed that the coordination number of Pb(II) is eight with six O-donor atoms from the tfpb ligand and two F-donors from anionic ligands. The 3D supramolecular structure of 1 is realized by weak directional C–F···F–C and π–π stacking interactions. After calcination of nano-sized 1 at 500?°C, pure phase nano-sized lead(II) oxide is produced.     

Solvothermal Synthesis of a Nano-sized Aza-aromatic Base Adduct of a Cadmium(II) 4,4-Difluoro-1-phenyl-1,3-butandionate Coordination Compound

A new nano-structured cadmium(II) coordination compound, [Cd(phen)(dfpb)₂] (1) (phen?=?1,10-phenanthroline, dfpb?=?4,4-difluoro-1-phenyl-1,3-butandion), was synthesized by a solvothermal method and produced a coordination polymer in the nano-size range. The new nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction elemental analysis and IR spectroscopy. Compound 1 was structurally characterised by single crystal X-ray diffraction. The single crystal structure shows a coordination number for the Cd ion of six with two N-donor atoms from the phen ligand and four O-donors from the two dfpb moieties. Self-assembly occurs by CH····F–C and π–π stacking interactions. The supramolecular features in these complexes are controlled by weak directional intermolecular interactions.     

Analysis and Optimization of a Synthetic Milkweed Floral Attractant for Mosquitoes

A pentane extract of flowers of common milkweed, Asclepias syriaca (Asclepiadaceae), elicited significant orientation from both male and female Culex pipiens in a dual-port flight olfactometer. Analysis of the extract by gas chromatography-mass spectrometry revealed six major constituents in order of relative abundance: benzaldehyde, (E)-β-ocimene, phenylacetaldehyde, benzyl alcohol, nonanal, and (E)-2-nonenal. Although not all were collected from the headspace profile of live flowers, a synthetic blend of these six compounds, when presented to mosquitoes in the same levels and proportions that occur in the extract, elicited a response comparable to the extract. Subtractive behavioral bioassays demonstrated that a three-component blend consisting of benzaldehyde, phenylacetaldehyde, and (E)-2-nonenal was as attractive as the full blend. These findings suggest the potential use of synthetic floral-odor blends for monitoring or control of both male and female disease-vectoring mosquitoes.     

Vacuum desorption of gases from inorganic solvents with various boiling points

The vacuum desorption of gases from inorganic solvents with low and high boiling points is reported. A thin-film evaporator consisting of regular tubular packing elements is considered. A laminar downward cocurrent flow of liquid and vapor is analyzed. General theoretical propositions are illustrated by the example of the desorption of simple gases from lower alcohols (methanol, ethanol) and liquid naphthalene, as well as by the example of removing the products of ester decomposition from esters at high temperatures.     

Investigating the effect of nano-silica on efficiency of the foam in enhanced oil recovery

Due to the vast production of crude oil and consequent pressure drops through the reservoirs, secondary and tertiary oil recovery processes are highly necessary to recover the trapped oil. Among the different tertiary oil recovery processes, foam injection is one of the most newly proposed methods. In this regard, in the current investigation, foam solution is prepared using formation brine, C₁₉TAB surfactant and air concomitant with nano-silica (SiO₂) as foam stabilizer and mobility controller. The measurements revealed that using the surfactant-nano SiO₂ foam solution not only leads to formation of stable foam, but also can reduce the interfacial tension mostly considered as an effective parameter for higher oil recovery. Finally, the results demonstrate that there is a good chance of reducing the mobility ratio from 1.12 for formation brine and reservoir oil to 0.845 for foam solution prepared by nanoparticles.     

Volume fraction measurement and flow regime recognition in dynamic gas–liquid two phase flow using gamma ray radiation technique

Gas–liquid two phase f low is probably the most important form of multiphase f lows and is found widely in industrial applications, particularly in the oil and petrochemical industry. In this study, in the first instance a gas–liquid two phase f low test loop with both vertical and horizontal test tube was designed and constructed. Different volume fractions and f low regimes were generated using this test loop. The measuring system consists of a ¹³⁷Cs single energy source which emits photons with 662 keV energy and two 1-inch NaI (Tl) scintillation detectors for recording the scattered and transmitted counts. The registered counts in the scattering detector were applied to the Multi-Layer Perceptron neural network as inputs. The output of the network was gas volume fraction which was predicted with the Mean Relative Error percentage of less than 0.9660%. Finally, the predicted volume fraction via neural network and the total count in transmission detector were chosen as inputs for another neural network with f low regime type as output. The f low regimes were identified with mean relative error percentage of less than 7.5%.