Predicting Detonation Performance of CHNOFCl and Aluminized Explosives

A new “hand‐calculated” method is introduced for prediction of detonation pressure of explosive and mixture of explosives with general formula CHNOFClAl. Suitable decomposition paths are used to estimate heat of detonation and detonation pressure. These decomposition paths are based on the distribution of oxygen atoms between carbon and hydrogen atoms as well as the degree of oxidation of aluminum. For CHNOFCl explosives, it is shown that the predicted detonation pressures with the new method are more reliable with respect to one of the best available empirical methods for loading densities greater than or equal 0.8 g cm⁻³. Since aluminized explosives have non‐ideal behavior, the new method does not require using full or partial oxidation of aluminum, which is usually required by a computer code. The predicted results of the new model also provide more reliable results than outputs of complex computer code with the BKWS equation of state.     

Fabrication of 5052Al/Al2O3 nanoceramic particle reinforced composite via friction stir processing route

In this research, microstructure and mechanical properties of 5052Al/Al₂O₃ surface composite fabricated by friction stir processing (FSP) and effect of different FSP pass on these properties were investigated. Two series of samples with and without powder were friction stir processed by one to four passes. Tensile test was used to evaluate mechanical properties of the composites and FSP zones. Also, microstructural observations were carried out using optical and scanning electron microscopes. Results showed that grain size of the stir zone decreased with increasing of FSP pass and the composite fabricated by four passes had submicron mean grain size. Also, increase in the FSP pass caused uniform distribution of Al₂O₃ particles in the matrix and fabrication of nano-composite after four passes with mean cluster size of 70 nm. Tensile test results indicated that tensile and yield strengths were higher and elongation was lower for composites fabricated by three and four passes in comparison to the friction stir processed materials produced without powder in the similar conditions and all FSP samples had higher elongation than base metal. In the best conditions, tensile strength and elongation of base material improved to 118% and 165% in composite fabricated by four passes respectively.     

Study of electrophoretic deposition of ZnS:Ag/CNT composites for luminescent applications

In present work, electrophoretic deposition of novel photoluminescence (PL) composites of ZnS:Ag/carbon nano tube (CNT) on the surface of Al substrates was investigated. In deposition process, CNT concentration and applied coating voltage were studied as the effective parameters. Deposition weight showed the reverse relationship with the amount of concentration and direct dependence to the applied voltages. Furthermore, current densities were decreased with increasing CNT concentrations up to 12.5 wt%, and increased strongly with further CNT concentrations. Moreover, applied voltage and current density show the same positive trends. Other results revealed that PL emission intensities were significantly quenched with increasing the CNT concentration. Nevertheless, PL intensities were improved with increasing applied voltage up to 300 V, but reduced with further voltage increase. Morphological studies of ZnS:Ag/CNT composites confirmed that the intertwined architecture was formed by wrapping of CNTs on the surfaces of ZnS microsize particles.     

Effect of membrane clarification on the physicochemical properties of pomegranate juice

Pomegranate juice (PJ) has a turbid appearance which can be clarified by membrane processing. The effect of membrane processing with hydrophilic polyvinylidene fluoride with pore sizes of 0.22 and 0.45 μm and mixed cellulose esters (MCE) with pore sizes of 0.22, 0.1, and 0.025 μm on physicochemical properties of PJ were evaluated. Turbidity, suspended solids, acidity, total soluble solids, total phenolic content and antioxidant activity decreased after passing through the membrane at the same rate for all membranes tested. Total soluble solids content (with mean rejection factor = 20.8%) and antioxidant activity (Efficient concentration 50 was duplicated) had the smallest and the greatest reduction in all membranes, respectively. Also, five important anthocyanins identified by LC/MS decreased after PJ clarification at the same rate for all membranes. Pelargonidin 3‐glucoside had minimum reduction (mean rejection = 7.7%). Ellagic acid also decreased for all membranes. However, MCE 0.025 μm membrane resulted in a greater decrease than did the other membranes (mean rejection = 24.3%).     

Mutual Information Games in Multiuser Channels With Correlated Jamming

We investigate the behavior of two users and one jammer in an additive white Gaussian noise (AWGN) channel with and without fading when they participate in a noncooperative zero-sum game, with the channel's input/output mutual information as the objective function. We assume that the jammer can eavesdrop on the channel and can use the information obtained to perform correlated jamming. We also differentiate between the availability of perfect and noisy information about the user signals at the jammer. Under various assumptions on the channel characteristics, and the extent of information available at the users and the jammer, we show the existence, or otherwise nonexistence of a simultaneously optimal set of strategies for the users and the jammer, and characterize those strategies whenever they exist.     

United Versus Cooperative Spectrum Sensing in Cognitive Wireless Sensor Networks (C-WSNs)

Wireless Personal Communications - Cooperation is an effective method to increase the performance metrics of spectrum sensing in cognitive radio (CR). For spectrum sensing in cognitive wireless...     

On the relevance of fair sampling assumption in the recent Bell photonic experiments

In the experimental verification of Bell's inequalities in real photonic experiments, it is generally believed that the so-called fair sampling assumption (which means that a small fraction of results provide a fair statistical sample) has an unavoidable role. Here, we want to show that the interpretation of these experiments could be feasible, if some different alternative assumptions other than the fair sampling were used. For this purpose, we derive an efficient Bell-type inequality which is a CHSH-type inequality in real experiments. Quantum mechanics violates our proposed inequality, independent of the detection-efficiency problems.     

Gas transport behavior of DMDCS modified MCM-48/polysulfone mixed matrix membrane coated by PDMS

Mesoporous MCM-48 silica was synthesized by templating method and the structure of particles was characterized by XRD, TEM and N₂ adsorption techniques. The surface modification of particles in order for introducing into PSF matrix was performed by dimethyldichlorosilane (DMDCS) silylation agent. SEM images of as-synthesized and modified MCM-48/PSF MMMs indicate that in the modified MCM-48 silica particles adhered well to the PSF matrix and that the synthesized MMMs were defect free. The incorporation of MCM-48 particles in to the PSF matrix and also surface coating of these MMMs by polydimethylsiloxane (PDMS) were performed. The quality of surface coating was investigated by SEM images and permeability tests. For all gases tested (N₂, CO₂, CH₄ and O₂), the permeabilities increased in proportion to the weight percent of MCM-48 present in the film and the calculated CO₂/CH₄ and O₂/N₂ selectivities of PDMS coated membranes showed enhancement in ideal and actual selectivities both.     

In Situ Solvothermal Crystallization of TiO2 Nanostructure on Alumina Granules for Photocatalytic Wastewater Treatment

Synthesis of nanostructure titania powders and in situ crystallization of anatase coating layer on sintered alumina granules by solvothermal method were investigated. In coating process, addition of polyvinyl alcohol (PVA) as binder to solvothermal solution was also studied. Microstructure analyses of powders showed that crystallization and growth of nanostructure anatase phase in a thin gel layer were enhanced with temperature increase. The titania nanopowders synthesized at 120 °C and 8 h represented photodegradation of methyl orange solution as model wastewater up to maximum 94% yield in slurry photoreactor. However, in coating process, with increasing temperature to 220 °C and coating time to 24 h, adhesion and photocatalytic properties of the coated layer were improved. Furthermore, PVA binder addition led to formation of more uniform layer with less attrition loss in the reactor.