Effect of salts and their interaction with ingenious surfactants on the interfacial tension of crude oil/ionic solution

Understanding the roles of asphaltene and resin as natural surfactants existed in crude oil can enlighten contradicting reported results regarding interfacial tension(IFT) of crude oil/aqueous solution as a function of salinity and ion type. In this way, this study is aimed to investigate the effect of these natural surface active agents on IFT of with special focus on SO_4~(2-)anion and Mg~(2+)cation. Two different synthetic oil solutions of 8 wt% of the extracted asphaltene and resin dissolved in toluene are prepared, and then IFT values are measured. After that,the obtained results are compared with the IFT of intact crude oil in contact with the same saline solutions examined in the previous stage. The obtained results showed a synergistic effect of Na_2SO_4+ MgCl_2 solution unlike the MgSO_4+ MgCl_2 and CaSO_4+ MgCl_2 solutions on IFT reduction of resin at MgCl_2 concentration of 15000 mg·kg~(-1). In summary, it is found that the affinity of asphaltene molecules towards the interface of oleic phase/ionic solution leads to higher IFT variation.     

Light and scanning electron microscopic features of the tongue in cattle egret

Adult individuals of both sexes were sacrificed by decapitation and their tongues were teared out in order to be investigated. Cattle egret's tongue is distinguished into the apex, body, and root regions. A shallow median sulcus is apparently noticed on the dorsal surface of the tongue's body only. Histologically, the tongue mucosa is covered with a thick parakeratinized epithelium. The dorsal epithelia of the apex and body are densely packed with exfoliated superficial cells. However, the dorsal surface showed microridges observed on the surface epithelial cells. In the body region, the gland's outlets are integrated in glandular patches on the top of keratinized folds at both sides of the median sulcus. The ventral surface of the tongue is devoid of any glandular outlets. The egret's tongue is supported by a paraglossum cartilage wrapped up with a fibrous perichondrium and striated muscle fibers. It extends ventrally as paraglossale apex then flattened in the body giving the corpus paraglossale which bifurcates caudally in the root giving paraglossalis caudalis. The tongue exhibits certain features that are unique as an adaptation to food intake, the type of food, lifestyles and bird's habitat with no any sex‐specific differences. Microsc. Res. Tech. 79:595–603, 2016. © 2016 Wiley Periodicals, Inc.     

Technology selection in the presence of fuzzy data and dual-role factors

Technology selection is an important part of management technology. One of the models which is used for technology selection is data envelopment analysis (DEA). Conventional DEA models require input and output data to be precisely known, and also they assume that decision making units do not have dual-role factor, but this is not always the case in real applications, such as technology selection. In this regard, a model for technology selection in the presence of fuzzy data and dual-role factors is developed in the present study. A numerical example demonstrates the application of the proposed method.     

Two‐Microphone Binary Mask Speech Enhancement in Diffuse and Directional Noise Fields

Two‐microphone binary mask speech enhancement (2mBMSE) has been of particular interest in recent literature and has shown promising results. Current 2mBMSE systems rely on spatial cues of speech and noise sources. Although these cues are helpful for directional noise sources, they lose their efficiency in diffuse noise fields. We propose a new system that is effective in both directional and diffuse noise conditions. The system exploits two features. The first determines whether a given time–frequency (T‐F) unit of the input spectrum is dominated by a diffuse or directional source. A diffuse signal is certainly a noise signal, but a directional signal could correspond to a noise or speech source. The second feature discriminates between T‐F units dominated by speech or directional noise signals. Speech enhancement is performed using a binary mask, calculated based on the proposed features. In both directional and diffuse noise fields, the proposed system segregates speech T‐F units with hit rates above 85%. It outperforms previous solutions in terms of signal‐to‐noise ratio and perceptual evaluation of speech quality improvement, especially in diffuse noise conditions.     

Stability analysis of whirling composite shells partially filled with two liquid phases

In this paper, the stability of whirling composite cylindrical shells partially filled with two liquid phases is studied. Using the first-order shear shell theory, the structural dynamics of the shell is modeled and based on the Navier-Stokes equations for ideal liquid, a 2D model is developed for liquid motion at each section of the cylinder. In steady state condition, liquids are supposed to locate according to mass density. In this study, the thick shells are investigated. Using boundary conditions between liquids, the model of coupled fluid-structure system is obtained. This coupled fluid-structure model is employed to determine the critical speed of the system. The effects of the main variables on the stability of the shell are studied and the results are investigated.     

Separation of trace amounts of palladium from water and wastewater samples using MPTMS-SBA-15 mesoporous silica sorbents

This study describes the application of functionalized Santa Barbara Amorphous mesoporous silica as an easily prepared and stable solid sorbent for the separation of trace amounts of palladium (Pd) ions in aqueous solutions. The mesoporous silica was functionalized by 3-mercaptopropyltrimetoxysilane, and its application as solid sorbents for the preconcentration of Pd ion was studied. Different experimental conditions such as pH, type and concentration of eluent solution were optimized. The in?uence of various interferences ions on the recovery of Pd(II) was investigated. In the optimized condition, the recovery was greater than 98.3%. The maximum adsorption capacity was obtained 146.2 mg g^?1 for the modified sorbent. The proposed procedure was applied for the separation and preconcentration of Pd in water and wastewater samples.     

Copolymerization of acrylonitrile with N-substituted maleimides

Acrylonitrile was copolymerized with three N-arylmaleimides as well as with N-octadecylmaleimide in dimethylformamide (DMF) using azobisisobutyronitrile (AIBN) as initiator. The monomer reactivity ratios were calculated by the Fineman-Ross and the Kelen-Tüd?s methods from which the Q- and e-parameters of these monomers were evaluated. The prepared copolymers were characterized by viscosity measurements and thermal analysis. The intrinsic viscosity decreases by increasing the maleimide content in the copolymer. Thermogravimetry TG and differential thermal analysis (DTA) data showed a remarkable improvement in the thermal behaviour of the investigated copolymers. A mechanism for the participation of the maleimide units in the nitrile oligomerization was also proposed. The investigation of the dyeing properties of the copolymers with the exception of those containing octadecylmaleimide, showed good affinity towards basic dyes as well as an appreciable improvement in their colour fastness towards UV light.     

Experimental characterization of fracture of glass fiber reinforced composites laminates subjected to freeze‐thaw cycles

The simultaneous effect of moisture and freeze‐thaw cycle on the mechanical behavior of glass/epoxy composites laminates is experimentally investigated. The study is planned in order to simulate the detrimental presence of humidity due to rainfall in surface damage of composite structures operating in cold weather. Different mechanisms governing the monotonic response of specimens subjected to freeze‐thaw cycles are pointed out by taking advantages of SEM images. Comparing SEM images taken from dry and wet specimens shows that the failure mechanisms such as matrix cracking and delamination are vastly activated around the notched region when the material is exposed to humidity and freeze‐thaw cycle. The load‐displacement response of examined specimens, namely the linear response, is remarkably altered under these conditions. A reduction of approximately 40% in ultimate load and 30% in slope of tangent line of load‐displacement curves is identified after 100 cycles of freeze‐thaw as well as more than 20% decrease of strain energy release rate.     

Charge-transfer complexes as polymerization inhibitors: 2. Studies on the mechanism of inhibition of the radical polymerizations of acrylonitrile and vinyl acetate using the amine-chloranil complexes

The mechanism of inhibition of the bulk and solution polymerizations of acrylonitrile (AN) and vinyl acetate (VA) has been investigated using the charge-transfer complexes of triethylamine (TEA) and N,N-dimethylaniline (DMA) with chloranil. Complete inhibition is achieved by the complexes of both amines for the polymerizations of both monomers. The greater inhibiting efficiency of the TEA complexes is explained in terms of their greater stabilities. The results support the idea that inhibition by quinones involves electron-transfer from the polymeric radicals to the quinone forming molecular complexes of polymeric cations and semiquinone anions. The latter are the actual inhibitors so that the efficiency of inhibition depends on the feasibility of their formation which is determined by the stability of the complexes formed. The nature of the inhibition reaction products is determined by the extent to which the semiquinone anions are found as kinetically independent species in the polymerizing system. The mechanism suggested accounts for the great differences in the inhibiting powers of quinones for the polymerizations of various monomers.     

First-principles insight into two-dimensional palladium phosphide tellurium (PdPTe) monolayer as a promising scavenger for detecting SF6 decompositions

Journal of Materials Science - Recently, the monitoring of SF6 decomposition components has allured notable attention. SF6 decomposition products are toxic and corrosive, which will greatly reduce...