Experimental investigation of pool boiling characteristics of low-concentrated CuO/ethylene glycol–water nanofluids

Boiling heat transfer performance of nanofluid has been studied during the past few years. Some controversial results are reported in literature about the potential impact of nanofluids on heat transfer intensification. Whereas the mixtures of ethylene glycol and water are considered the most common water-based antifreeze solutions used in automotive cooling systems, the present study is an experimental investigation of boiling heat transfer of CuO/ethylene glycol–water (60/40) nanofluids. The results indicate that a considerable boiling heat transfer enhancement has been achieved by nanofluid and the enhancement increases with nanoparticles concentration and reaches 55% at a nanoparticles loading of 0.5%.     

Oxidative dehydrogenation of propane over vanadium catalyst supported on nano-HZSM-5

Vanadium catalyst supported on nano-HZSM-5 was utilized in oxidative dehydrogenation of propane to propylene. The physicochemical properties of the elaborated catalysts were investigated by means of XRD, SEM, FTIR spectra, UV-vis, Raman, NH₃-TPD and H₂-TPR techniques. The effect of vanadium loading (2–10 wt %), temperature (500–600°C) and oxygen to propane ratio (0.5–1.5) on conversion, propylene and ethylene selectivity was studied using full factorial design of experiments. The obtained data were statistically analyzed using the Analysis of Variance (ANOVA) and a p < 0.05 was considered statistically significant. The mathematical relationship of conversion, propylene and ethylene selectivity on three independent variables approximated by a second-order quadratic model. Two-dimensional contour plots were drawn to investigate the effect of independent variables and their interaction on the chosen responses. The function of temperature, oxygen to propane ratio and vanadium content such as acidity and reducibility on the performance of supported vanadium catalysts were discussed.     

Application of a weakly compressible smoothed particle hydrodynamics multi-phase model to non-cohesive embankment breaching due to flow overtopping

The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The governing equations of the present model are the Navier-Stocks equations solved using Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) method. To simulate the movement of sediment particles, the model considers a powerful two-part technique; when the sediment phase has rigid behavior, only the force term due to shear stress in the Navier-Stokes equations is used for simulation of sediment particles’ movement. Otherwise, all the Navier-Stokes force terms are used for transport simulation of sediment particles. In the present model, the interactions between different phases are calculated automatically, even with considerable difference between the density and viscosity of phases. Validation of the model is performed using simulation of available laboratory experiments, and the comparison between computational results and experimental data shows that the model generally predicts well the flow propagation over movable beds, the induced sediment transport and bed changes, and temporal evolution of embankment breaching.     

Mass spectrometric analysis of polymers derived from N-aryl-α-amino acid initiators

Previous studies have demonstrated that the interaction of carboxylic acids with aryl amines produces free radicals that can initiate the polymerization of acrylic monomers. N-Aryl-α-amino acids (NAAA) represent a special class of this type of initiator that combines in one molecule the carboxylic acid and aryl amine functionalities necessary for the generation of radical species. The mechanism(s) of radical formation in these molecules is thought to involve both electron transfer and hydrogen abstraction reactions that can occur by intra- and intermolecular pathways. Acrylic monomers, i.e., methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), were activated with various amounts of several NAAAs. Specific NAAAs investigated include N-phenylglycine (NPG) and N-p-tolylglycine (NTG). Polymerization was conducted at ambient or near ambient temperatures, and the polymers then were analyzed by electron impact mass spectrometry. Results indicate that these polymers have end groups derived directly from the NAAA initiators. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:561–565, 1997     

Incorporation of oleic acid and eicosapentaenoic acid into glycerolipids of cultured normal human fibroblasts

Confluent skin fibroblasts from normal humans were incubated in serum free medium with up to 100 nmole/mL eicosapentaenoic acid (EPA; bound to albumin in a 4.6∶1 ratio) and compared with cells incubated with oleic acid (OA) at similar concentrations. The rate of [¹⁴C]OA incorporation into triacylglycerol (TG) (nmol/mg/h) was approximately 5-fold greater than that of [¹⁴C]EPA. The mass of TG formed after incubation of fibroblasts with EPA was also significantly lower than that formed with OA (43.2 ±9.3vs. 59.5±6.6 μg/mg cell protein, respectively,P=0.006). The addition of excess, unlabeled EPA reduced the rate of incorporation of [¹⁴C]OA into TG whereas unlabeled OA stimulated incorporation of [¹⁴C]EPA into TG. When the cells were preincubated with human serum basic proteins (BP I, II and III), the mass of TG formed (compared to baseline) was significantly higher with the basic proteins whether OA or EPA was studied. Only BP I significantly stimulated the mass of cell phospholipids, an effect that occurred with either OA or EPA in the medium. The results suggest that in cultured normal human fibroblasts, OA is a better substrate for TG synthesis than EPA and that this effect may be accentuated by the presence of the basis proteins.     

Underground Leakage into Freezing Ground

Certrifuge model tests are used to identify the path of dyed ethylene glycol (antifreeze) when it leaks from a cylinder buried in freezing or frozen silt at different times during the freezing cycle. The paths followed are contrasted to the path followed by release of dyed water from the same cylinder in a model undergoing freezing, and in another model, to the path followed by release of the ethylene glycol from the cylinder into soil not subjected to freezing. When ethylene glycol is released after freezing has penetrated well below the elevation of the leak, it is contained, at least over that duration (simulating 0.4 years), by the surrounding ice rich frozen soil. The same behavior is observed when ethylene glycol is released into unfrozen soil that experiences no subsequent freezing. When ethylene glycol is released before freezing, subsequent freezing draws the contaminant vertically to the soil surface. When it is released as freezing is occurring at the elevation at which the ethylene glycol is released, its path is long and inclined upward, moving far from the point of injection; dyed water released at the same elevation and at the same point during the freezing process does not travel far from the point of injection before being frozen in place.     

A coloured polyester fabric with antimicrobial properties conferred by copper nanoparticles

In this study, we aimed to produce a coloured polyester fabric through the in situ sonosynthesis of copper nanoparticles using copper sulphate, hydrazine, sodium hydroxide and polyvinylpyrrolidone. The treated fabrics were characterised by X‐ray diffraction, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and elemental mapping. Moreover, mechanical properties, wettability and antibacterial/antifungal activities of the treated fabrics were evaluated. Central composite design based on the response surface methodology was used to study the effect of copper sulphate, hydrazine hydrate and sodium hydroxide on the weight gain and colour of the treated fabrics. In addition to their roles as reducing agents, hydrazine and sodium hydroxide were responsible for the simultaneous aminolysis and hydrolysis of polyester, increasing the adsorption of nanoparticles on the surface. According to the results, the reddish brown samples treated with copper nanoparticles showed excellent antibacterial and antifungal efficiencies, improved tensile strength and decreased wettability.