Electrical and structural properties of polyaniline/cellulose triacetate blend films

Polyaniline (PANI) has been blended with cellulose triacetate (CTA) to obtain both good mechanical properties and good electrical properties. The effects of PANI weight percentage on the optical, structural, morphological and electrical properties in the blend films of polyaniline and cellulose triacetate (PANI/CTA) have been investigated. The phenomenon of percolation was observed in these blend films. It is found that the electrical conductivity of the blend films increases with the increase of polyaniline content up to a value of 10⁻⁴ S cm⁻¹ at 84 weight percentage of PANI. The experimental percolation threshold of the dried blend films is obtained at 9.5 wt% of polyaniline. The values of Mott’s temperature, density of states at the Fermi level [N (E _f)], hopping distance (R _hop), and barrier height (W _hop) for PANI/CTA blend films are calculated. By applying Mott’s theory, it is found that the PANI/CTA blend films obey the three dimensional variable range hopping mechanism.     

Model tree approach for predicting uniaxial compressive strength and Young’s modulus of carbonate rocks

Bulletin of Engineering Geology and the Environment - The uniaxial compressive strength (UCS) and Young’s modulus (E) of rock are important parameters for evaluating the strength,...     

Structural,rheological, and mechanical properties of PA6/SAN/SEBS ternary blend/organoclay nanocomposites

The aim of this study was to investigate the effect of nanoclay addition on the morphological and mechanical properties of PA6/SAN/SEBS ternary blend. Two different nanoclays with different modifiers and two different mixing sequences were used to investigate the role of thermodynamic and kinetic, respectively, in the nanoclays localization. XRD, SEM, TEM, melt rheology, tensile and Izod impact tests were used to characterize the nanocomposites. Results of characterization of nanocomposites showed that clay localization is a very influential parameter to determine the type of morphology and, consequently, mechanical properties of ternary/clay nanocomposites. It was demonstrated that presence of nanoclay in the matrix results in the increase of stiffness, while localization of nanoclay at the interface improves the toughness and tensile strength. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41969.     

Preparation of shish‐kebab and nanofiber polyethylene with chromium/Santa Barbara amorphous silica‐15 catalysts

Cr/SBA‐15 catalysts were prepared by the grafting of chromium nitrate nonahydrate [Cr(NO₃)₃·9H₂O] complexes onto SBA‐15 mesoporous materials. Shish‐kebab and nanofiber polyethylenes (PEs) were prepared under different temperatures via ethylene extrusion polymerization with the Cr(NO₃)₃·9H₂O catalytic system. The diameter of a single nanofiber was 100–250 nm. Scanning electron microscopy images showed that the polymer obtained from the SBA‐15‐supported catalyst under different polymerization temperatures produced nanofiber and/or shish‐kebab morphologies. X‐ray diffraction and differential scanning calorimetry were used to characterize microstructures of the materials. Polymers obtained with all of the catalysts showed a melting temperature, bulk density, and high load melt index; this indicated the formation of linear high‐density PE. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and structure study of copolymers from thiadiazole fused indolocarbazole and dithienosilole

We report synthesis and characterization of two D-A polymers (PSDT-C12 and PSDT-EH) with different side chains. Both polymers are based on alternate 12,13-dioctyl-indolo[2,3-a][1,2,5]thiadiazolo[3,4-c]carbazole (TDZIC) and dithienosilole derivative units in polymer main chain. We used TDZIC to enlarge the 2D conjugated plane of acceptor monomers by fusing benzothiadiazole (BT) unit with an indole unit having alkyl groups. PSDT-C12 exhibited 10 nm redshift compared to PSDT-EH in solid films, while their absorption spectra were almost identical in solutions. Since the backbone and side chains on the indolocarbazole group are the same, the redshift on PSDT-C12 could be resulted from the dodecyl (C12) side chain on the dithienosilole unit and different molecular weight between these two polymers. PSDT-C12 has a larger molecular weight than PSDT-EH. Therefore possibly both side chains and molecular weight contributed to the difference in the absorption spectra in solid films. The straight C-12 side chain has less steric hindrance than the branched EH side chain in solid films. PSDT-C12 has a longer main chain (larger molecule weight) than PSDT-EH, which can favour a more extended main chain interaction. The vibronic peak at 519 nm and shoulder at 563 nm in the PSDT-C12 film further confirmed stronger main chain interaction. Geometry optimization showed that head–tail (HT)-PSDT had a more twisting conjugated backbone with larger dihedral angle between dithienosilole unit and thiadiazole-fused ring compared to head–head/tail–tail (HH/TT)-PSDT.     

A probabilistic model for assessing the reliability of wind farms in a power system

Modeling the generation of a wind farm and its effect on power system reliability is a challenging task, largely due to the random behavior of the output power. In this paper, we propose a new probabilistic model for assessing the reliability of wind farms in a power system at hierarchical level II (HLII), using a Monte Carlo simulation. The proposed model shows the effect of correlation between wind and load on reliability calculation. It can also be used for identifying the priority of various points of the network for installing new wind farms, to promote the reliability of the whole system. A simple grid at hierarchical level I (HLI) and a network in the north-eastern region of Iran are studied. Simulation results showed that the correlation between wind and load significantly affects the reliability.     

A decision-process model of relational risk and governance and their impact on performance

The purpose of this paper is to investigate the link among risk, governance, and performance. In order to achieve this objective, the paper examines the impact of relational risk on governance decision options (trust, bilateral control, and unilateral control) and performance (design time). Survey research was conducted to collect data from 221 new product development (NPD) relationships and structural equation modeling was conducted to test the hypotheses. The results suggest that relational risk influences trust and bilateral control negatively and unilateral control positively. Results also indicated that trust and bilateral control are positively related to shortened design time while unilateral control and shortened design time are negatively related. We also found that there are threshold effects for modes of governance decision as they influence shortened design time. This study enhances the understanding of NPD relationships by examining the key mechanisms through which governance decision modes are influenced and how they influence NPD performance. In summary, this study shows how relational risk perception through affecting governance decision modes influence shortened design time.     

Synthesis Gas and Zinc Production in a Noncatalytic Packed‐Bed Reactor

A noncatalytic packed‐bed reactor has been constructed for management of the reduction of ZnO by methane, which leads to co‐production of synthesis gas and zinc. The reactor consisted of a simple vertical pipe filled with ZnO pellets. These pellets underwent reaction with a pure methane flow. Experimental tests were conducted in the temperature range 860–995 °C at atmospheric pressure in an electrically heated reactor. The results showed complete chemical conversion of methane to synthesis gas in the aforementioned temperature range. In addition, analysis of the product solids indicated that the collected solids in the outlet of the reactor were entirely zinc. The maximum methane flow rates (149–744 mL min^–1) were adjusted to ensure complete chemical conversion of methane. These adjustments were performed for different bed heights at various operating temperatures. Analysis of the product gases revealed high quality synthesis gas production without the influence of methane cracking or other undesired side reactions in the experimental tests. Finally, the governing partial differential equations of the reactor modeling were solved by the finite element method. Consequently, the gaseous profiles along the reactor and the breakthrough curves were predicted and compared with the experimental tests.