Preparation of polyaniline/nickel oxide nanocomposites by liquid/liquid interfacial polymerization and evaluation of their electrical,electrochemical and magnetic properties

A novel route has been developed to synthesize polyaniline (PANI)/nickel oxide (NiO) nanocomposites via liquid/liquid interfacial polymerization where NiO and the initiator were dispersed in the aqueous phase and the monomer was dissolved in the organic phase. The synthesized samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet?visible absorption, X‐ray diffraction, and electrochemical, electrical conductivity and magnetic property measurements. NiO was dispersed uniformly within the PANI matrix. The composites exhibited noticeable improvement in thermal stability and electrical conductivity in comparison with pure PANI. The composites showed excellent electrochemical reversibility at a scan rate of 0.1 V s^?1 and good redox stability even up to 100 cycles. The room temperature magnetic hysteresis measurements show a low value of coercivity for the polymer composites in comparison with NiO. The remnant magnetization (M_r) values were found to be increased with increasing concentration of NiO in the composites. © 2013 Society of Chemical Industry     

Efficient test case generation for validation of UML activity diagrams

Unified Modeling Language (UML) is widely used as a system level specification language in embedded system design. Due to the increasing complexity of embedded systems, the analysis and validation of UML specifications is becoming a challenge. UML activity diagram is promising to modeling the overall system behavior. However, lack of techniques for automated test case generation is one major bottleneck in the UML activity diagram validation. This article presents a methodology for automatically generating test cases based on various model checking techniques. It makes three primary contributions: First, we propose coverage-driven mapping rules that can automatically translate activity diagram to formal models. Next, we present a procedure for automatic property generation according to error models. Finally, we apply various model checking based test case generation techniques to enable efficient test case generation. Our experimental results demonstrate that our approach can reduce the validation effort drastically by reducing both test case generation time and required number of test cases to achieve a functional coverage goal.     

Reduction of acrylamide formation by vanadium salt in potato French fries and chips

The effects of vanadyl sulphate on the formation of acrylamide have been studied in fried potato products, such as French fries and chips. Acrylamide formation was inhibited by 30.3%, 53.3% and 89.3% when the sliced potato strips were soaked in 0.001, 0.01 and 0.1 M vanadyl sulphate (VOSO₄) solutions, respectively, for 60 min before frying. Moreover, 57.7%, 71.4% and 92.5% inhibition of acrylamide formation was observed when chips were soaked in the respective vanadyl sulphate solution before frying. In a separate model reaction, a solution containing an equimolar concentration of l-asparagine and d-glucose showed a significant inhibition of acrylamide formation when heated at 150 °C for 30 min in the presence of vanadyl sulphate (VOSO₄). The results indicate that the binding of VO²⁺ to asparagine and the decrease in the pH of the potato samples resulted in a significant reduction of acrylamide formation in fried potato products.     

Similarity Solution to Hydromagnetic Flow Past a Continuously Moving Semi‐infinite Vertical Porous Plate with Large Suction

The problem of a two‐dimensional free convective mass transfer flow of an incompressible, viscous, and electrically conducting fluid past a continuously moving semi‐infinite vertical porous plate with large suction in the presence of a magnetic field applied normal to the plate is studied. The non‐linear partial differential equations governing the flow have been transformed by a set of similarity transformations into a system of non‐linear ordinary differential equations. The resulting system of the similarity equations are solved analytically adopting the perturbation technique. The expressions for the velocity field, temperature field, concentration field, induced magnetic field, drag coefficient, and the coefficient of the rate of heat and mass transfer at the plate are obtained. The results are discussed in details through graphs and tables to observe the effect of various physical parameters involved in the problem. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21097     

Preparation of diamond like carbon thin films above room temperature and their properties

Diamond like carbon (DLC) thin films were deposited on p-type silicon (p-Si), quartz and ITO substrates by microwave (MW) surface-wave plasma (SWP) chemical vapor deposition (CVD) at different substrate temperatures (RT ∼ 300 °C). Argon (Ar: 200 sccm) was used as carrier gas while acetylene (C₂H₂: 20 sccm) and nitrogen (N: 5 sccm) were used as plasma source. Analytical methods such as X-ray photoelectron spectroscopy (XPS), FT-IR and UV–visible spectroscopy were employed to investigate the structural and optical properties of the DLC thin films respectively. FT-IR spectra show the structural modification of the DLC thin films with substrate temperatures showing the distinct peak around 3350 cm^− 1 wave number; which may corresponds to the sp² C–H bond. Tauc optical gap and film thickness both decreased with increasing substrate temperature. The peaks of XPS core level C 1 s spectra of the DLC thin films shifted towards lower binding energy with substrate temperature. We also got the small photoconductivity action of the film deposited at 300 °C on ITO substrate.     

Interpenetrating ionomer–polymer networks obtained by the in situ polymerization in pores of PVdF sponges as potential membranes in PEMFC applications

This article presents studies on novel composite electrolytes having the structure of semi-interpenetrating polymer networks for possible application as an electrolyte in fuel cells. The electrolytes were synthesized by soaking the macroporous Kynar-Flex^® (copolymer of vinylidene fluoride and hexafluoropropylene) sponge with water solution of the ionomer followed by the in situ free-radical polymerization of the later. Two ionomers having different acidity-methacrylic acid and p-styrenesulfonic acid were tested. The ionic conductivity of proposed membranes measured for several systems was high enough for applications in fuel cell in the 20–90 °C temperature range. For higher temperatures, the conductivity decreased because of the membrane drying. The fraction of water in the electrolytes was determined using weight loss analysis. The influence of inorganic filler addition and cross-linking ratio on physicochemical and electrochemical properties of the membranes were also tested.     

The effect of receptor-polymer matrix compatibility on properties of PEO-based polymer electrolytes containing a supramolecular additive: Part 1. Studies on phenomenon of compatibility

This paper presents the results of studies of poly(ethylene oxide)-based solid polymer electrolyte with the addition of anion receptor. The main stress is put on the influence of the anion receptor-polymeric matrix compatibility on the morphology of the composite. The comparison of the properties of two supramolecular compounds (calix[4]arene derivatives) having identical groups active in anion coordination in the narrow rim but with wide rim modified by groups having structure non-compatible and compatible to poly(ethylene oxide), is analyzed. The research of the system is made by means of vibrational (both IR and Raman) spectroscopies to evaluate the anion receptor-polymer–salt interactions. Raman and EDS mapping are used to determine the local concentration of the additive and salt. DSC and XRD determine the membrane crystallinity. Imaging techniques (both SEM and polarized light micrographs) allow to observe the morphology of membrane surface. The presented results show that additive distribution depends on the type of the receptor used and the phase of the polymer matrix (amorphous or crystalline).     

Motor and sensory evoked potential studies in brainstem strokes

BACKGROUND: Anterior chamber miotic solutions are widely used during anterior chamber surgery. We examined the effects of solutions containing miotic agents such as carbachol and/or acetylcholine on corneal endothelial pumping activity. METHODS: We monitored, in vitro, the transendothelial electrical potential difference of isolated rabbit corneal endothelial preparations. As controls, we used solutions without miotics. RESULTS: We found that a solution containing 55 mM acetylcholine and minimal amounts of salts (Miochol E) maintains transendothelial electrical potential difference some 30% above control levels for up to 4 h. Two other solutions, one including balanced salts and 0.55 mM carbachol (Miostat), the other a mixture of 0.19 mM carbachol and 55 mM acetylcholine plus minimal salts, are adequate to maintain the potential difference at control levels. Lastly, a solution with acetylcholine but without any salts (Miochol) greatly decreases the potential difference, to 30% of the control level, in 100 min. CONCLUSION: Our results indicate that: (1) 55 mM (1%) acetylcholine stimulates the endothelial electrical potential difference; (2) addition of 0.19 mM (0.003%) carbachol negates the stimulatory effect of acetylcholine; and (3) absence of electrolytes severely depresses the endothelial electrical activity.     

Detection of thiazide-based diuretics in equine urine by liquid chromatography/mass spectrometry

Thiazide-based diuretics are included in the list of banned drugs in the horse-racing industry. One effect of their misuse is increased urine flow, contributing to dilution of other doping agents. Their determination is essential in ensuring compliance to horse-racing regulation. This study evaluates the feasibility of using liquid chromatography/mass spectrometry (LC/MS) with electrospray and atmospheric pressure chemical ionization interfaces to analyze thiazidic diuretics in equine urine samples. Existing LC and gas chromatography/MS methods are limited in their applicability to thiazide analysis. Sample preparation, analyte extraction, chromatographic separation, ion-source collision induced dissociation, solvent composition, ionization mode, and ion polarity are discussed. The practicality of LC/MS for this analysis is demonstrated with actual equine administration samples collected at specified time intervals. Detection limits were 270 ng/mL for chlorothiazide, 131 ng/mL for hydrochlorothiazide, and 384 ng/mL for trichlormethiazide.