Novel drying additives and their evaluation for self-flowing refractory castables

The drying step of dense refractory castables containing hydraulic binders is a critical process, which usually requires using slow heating rates due to the high explosion trend of such materials during their first thermal treatment. Thus, this work investigated the performance of alternative additives to induce faster and safer drying of self-flowing high-alumina refractory castables bonded with calcium aluminate cement (CAC) or hydratable alumina (HA). The following materials were analyzed for this purpose: polymeric fibers, a permeability enhancing compound (RefPac MIPORE 20) and an organic additive (aluminum salt of 2-hydroxypropanoic acid). The drying behavior and explosion resistance of the cured samples were evaluated when subjecting the prepared castables to heating rates of 2, 5 or 20 °C/min and the obtained data were then correlated to the potential of the drying agents to improve the permeability and mechanical strength level of the refractories at different temperatures. The collected results attested that the selected additives were more efficient in optimizing the drying behavior of the CAC-bonded compositions, whereas the HA-containing castables performed better when the aluminum-based salt was blended with a small amount of CAC (0.5 wt%), which changed the binders hydration reaction sequence and optimized the permeability level of the resulting microstructure. Consequently, some of the designed compositions evaluated in this work showed improved drying behavior and no explosion was observed even during the tests carried out under a high heating rate (20 °C/min).     

(E)-Anethole microspheres as an alternative insecticide in funnel traps

Pyrethroids are the insecticides most commonly used inside traps, and the lack of alternatives poses the risk of pests developing resistance. In this paper we present two (E)-anethole formulations (spray drying (SD) and oil emulsion entrapment (OEE) processes) that provide a controlled release of their bioactive ingredient in the vapour phase with insecticidal potential in funnel traps.An experiment with the two pyralid moths Ephestia kuehniella Zeller and Plodia interpunctella Hübner was set up at two pilot stores in Spain for a four-month period. The microspheres (4 g of SD powder/trap or 6 g of OEE beads/trap) remained effective for 100 days, killing the moths by volatile activity. The efficacy values were within the interval of 70–100% for the first half of the experiment, with a decrease afterwards. The OEE beads performed better than did SD powder in the long run: over 80% efficacy for the whole experiment. The OEE process gives more loading capacity (19.7 g of (E)-anethole per 100 g of beads) and entrapment efficiency (28.6 g of (E)-anethole encapsulated per 100 g of (E)-anethole added) and is slower in releasing the product.In a laboratory study for E. kuehniella, the LC50 was 58.2 mg/L for SD after 24 h exposure to vapours and 111.6 mg/L for OEE after 48 h exposure to vapours. Therefore, the SD powder provides a quicker release of the bioactive ingredient.The results indicate that encapsulated (E)-anethole could be a promising insecticide for mass trapping, mating disruption and attract and kill strategies.     

Synthesis of porous Mg-doped CeO2 powders via self-propagating high-temperature synthesis route

The aim of this study was synthesis of Mg-doped porous cerium oxide powder by self-propagating high-temperature synthesis reaction of Mg-xCeO₂-O₂ system. Results indicated that doping Mg in the CeO₂ crystal structure increased its lattice parameter slightly, and shifted the Ce-O band in the FTIR spectra from 490 to 574 cm⁻¹. Moreover, the EDS results revealed the distribution of Mg in the CeO₂ microstructure. There were a high volume fraction of interconnected macro-pores in the microstructure of cerium oxide after the synthesis process. Increase in the x-value from 0.05 to 0.25 mol decreased the mean size and volume fraction of pores from 2.4 to 1 µm and 50 to 30 vol%, respectively. In addition, the BET surface area of porous CeO₂ varied between 0.3 and 1.57 m²/g. Finally, it was inferred that the SHS technique can be introduced as a rapid and novel method for synthesis of Mg-doped porous CeO₂ powders.     

Unique superstructure of Pd–Ir aerogel as a robust three-dimensional electrocatalyst

Herein, a novel, facile, fast, and one-step strategy is introduced to synthesize a three-dimensional (3D) Pd–Ir aerogel. The Pd–Ir aerogel is synthesized by reducing metallic ions in the presence of sodium carbonate and formaldehyde, followed by CO₂ supercritical drying. Controlling the type of generated nanostructures and the reaction kinetics is adjusted by the sodium carbonate concentration. The change of sodium carbonate concentration is employed for creating an efficient anisotropic condition to create a Pd–Ir aerogel. The aerogel depicts a 3D architecture with a large porosity and an ultra-low density (0.022 g cm^?3). This unique architecture illustrates the exceptional electrocatalytic activity and durability owing to the following vital reasons. The 3D architecture with large open pores not only significantly facilitates the accessibility of ethanol molecules to inner active sites but also guarantees the interaction of ethanol molecules with the surface of aerogel. Furthermore, the downfall of durability observed in the Pd/C owing to corrosion can eliminate by the self-supported nature of assembled aerogel. Moreover, the presence of Ir in the structure of aerogel leads to an alteration in the electronic structure of palladium, which facilitates the electrooxidation of ethanol at a high pH environment.     

Magnetically Recyclable Cufe2o4 Nanoparticles as an Efficient and Reusable Catalyst for the Green Synthesis of 2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane as CL-20 Explosive Precursor

Magnetic nanoparticles of copper ferrite (CuFe₂O₄ MNPs) have been simply prepared and applied as an efficient recyclable and reusable catalyst for the green synthesis of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0^5,9.0^3,11]dodecane (HBIW). The structure of the synthesized pure HBIW (recrystallization from ethanol) was confirmed by using various spectral techniques like infrared (IR), ¹H-NMR, ¹³C-NMR and some of its physical properties. The prepared catalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). In addition, CuFe₂O₄ MNPs could be reused up to seven runs without any significant loss of activity. Finally, the remarkable advantages of this method are the simple experimental procedure, shorter reaction times, simple workup, and green aspects by avoiding toxic catalysts and high yield of product.     

Parallel carbon nanotube stripes in polymer thin film with tunable microstructures and anisotropic conductive properties

It is known that shear-flow can induce units to assemble into vorticity-aligned stripe-structures in confined geometries. This study shows that the microstructure and the property of the stripe in polymer thin film can be well tuned by adjusting the viscosity ratio between dispersed phase and continuous phase. Polypropylene (PP)/poly(styrene–ethylene/butadiene–styrene) (SEBS)/octadecylamine functionalized multiwalled carbon nanotubes (ODA-MWCNTs) composites with different viscosity ratios were prepared by either pre-compounding ODA-MWCNT into PP or SEBS in a microcompounder. Under the induction of shear-flow, ODA-MWCNT and SEBS spontaneously assembled into vorticity-aligned stripes in PP thin films for all the composites with different viscosity ratios, resulting in the property of conductive anisotropy for the film. Interestingly, it was found that both the microstructures and the electrical properties of MWCNT stripes in PP thin films prepared from the composites with different viscosity ratios were significantly different.     

Automatic selection and fusion of color spaces for image thresholding

Automatic selection of color models has a great significance for machine vision purposes like image segmentation, object recognition, etc. Typically, selection of a proper color model is a problem that can just solve by testing the models on the target one by one. To achieve a proper color model, in this article, we propose a new method which is shaped on the basis of clustering and relation among models. The proposed method is verified experimentally for two different images (in thresholding purpose). The experimental results show that this method has a suitable power for automatic purposes.     

Performance analysis of a passive cooling system using underground channel (Naghb)

The present study, aims at introducing and studying the effect of an old and specific type of house cooling system in Bam city. Primary of the system is similar to Baud-Geers (wind tower) but in the mentioned system, there is an additional channel connected to Baud-Geer which is called Naghb. Naghb in fact is an underneath channel that uses the ground humidity to cool the air. Baud-Geer input wind passes through the Naghb and evaporation cooling makes it cooler in the Naghb. Therefore, the cooling effect of Baud-Geer enhances. Unfortunately, all of Baud-Geers and Naghbs in Bam destroyed in the earthquake happened on December 26, 2003 and only ruins of them are left, hence in order to study Naghb performance in the present study, a one-dimensional model is presented and the conservation equations of energy, mass and momentum have been solved simultaneously. In order to evaluate the model, a simple experimental setup is made on the basis of real dimensions of Naghb. The model results reveal the ability of Naghb in cooling the air during hot and dry months in Bam.     

Modeling,control, and simulation of grid connected intelligent hybrid battery/photovoltaic system using new hybrid fuzzy-neural method

Nowadays, photovoltaic (PV) generation is growing increasingly fast as a renewable energy source. Nevertheless, the drawback of the PV system is its dependence on weather conditions. Therefore, battery energy storage (BES) can be considered to assist for a stable and reliable output from PV generation system for loads and improve the dynamic performance of the whole generation system in grid connected mode. In this paper, a novel topology of intelligent hybrid generation systems with PV and BES in a DC-coupled structure is presented. Each photovoltaic cell has a specific point named maximum power point on its operational curve (i.e. current–voltage or power–voltage curve) in which it can generate maximum power. Irradiance and temperature changes affect these operational curves. Therefore, the nonlinear characteristic of maximum power point to environment has caused to development of different maximum power point tracking techniques. In order to capture the maximum power point (MPP), a hybrid fuzzy-neural maximum power point tracking (MPPT) method is applied in the PV system. Obtained results represent the effectiveness and superiority of the proposed method, and the average tracking efficiency of the hybrid fuzzy-neural is incremented by approximately two percentage points in comparison to the conventional methods. It has the advantages of robustness, fast response and good performance. A detailed mathematical model and a control approach of a three-phase grid-connected intelligent hybrid system have been proposed using Matlab/Simulink.