Optical and structural properties of electrodeposited polyaniline/Q‐CdS composites

HCl doped polyaniline (PANI)/Q‐CdS composite thin films have been synthesized using the electrodeposition route on indium tin oxide (ITO) coated glass substrates. Three different sizes of CdS quantum dots were uniformly dispersed in PANI matrix. As deposited samples were characterized by X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). Optical properties of the composite structures were investigated by using optical absorption, photoluminescence, and Raman spectroscopy. PANI/Q‐CdS composite showed significant improvement in the thermal behavior as indicated by thermogravimetric analysis (TGA) thermograph. Our results also indicated that the doping state of the nanocomposites was dependent on the size of the CdS nanoparticles and improved with decreasing size. POLYM. COMPOS., 35:1864–1874, 2014. © 2014 Society of Plastics Engineers     

Insights into discrepancy in power generation among glucose and malate grown Rubrivivax benzoatilyticus JA2 microbial fuel cells

In this study, Rubrivivax benzoatilyticus JA2^T (=ATCC BAA-35^T = JCM 13220^T = MTCC 7087^T), an anoxygenic photosynthetic bacterium, was subjected to altered conditions and observed for changes in power outcome in the two chambered microbial fuel cells (MFCs), the basis of which was established using metabolomic studies. This is an extension to our previous studies, which showed that, under photo heterotrophic conditions, glucose in the form of a solitary carbon resource in minimal media, caused the strain JA2 to exhibit altered growth rates, progressive loss of pigmentation and reduced cell size (3–4 μm), compared to malate grown cells (6–7 μm). When R. benzoatilyticus JA2 cells were grown in malate bio-anodes, they presented higher potentials (289.22 ± 4.6 mV or 436.22 OCV per mg dry weight) compared to glucose bioanodes (163 ± 5.5 mv or 188.98 OCV per mg dry weight). Insights from the metabolomic footprints and fingerprints have revealed differential regulation of key components in the central metabolic pathway such as fumarate, citrate and succinate, which are significantly increased in malate grown bio anodes. Strain JA2 cells when grown with malate as substrate are densely grown on the electrodes and exhibited reduced size, when observed under SEM, which contrasts with control cells grown on malate broth. The artificial selection pressure of the MFC and the different metabolic pathways followed by these bacteria are the reasons for such discrepancy in the power production by the strain JA2. These adaptations may indicate survival advantage during the electron transfer and growth in bio anodes. The study throws light on what types of effluents would be more suitable as substrates for R. benzoatilyticus JA2 microbial fuel cells.     

PVC membrane selective electrode for determination of cadmium(II) ion in chocolate samples

Benzil bis（carbohydrazone） （BBC） is prepared and explored as new NN Schiff’s base, which plays the role of an excellent ion carrier in the construction of a Cd（II） ion membrane sensor. The tris（2-ethylhexyl） phosphate best performance corresponds to a membrane composition of 30%poly （vinyl chloride）, 65%（TEHP）, 3.5%BBC and 1.5%tetradodecyl-ammoniumtetrakis（4-chlorophenyl） borate （ETH 500）. This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior （with slope of 29.7 mV per decade） over a very wide concentration range from 1.0×10^-1 to 1.0×10^-8 mol·L^-1 with a detection limit of 3.2×10^-8 mol·L^-1. It shows rela-tively fast response time in whole concentration range （〈8 s） and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate （EDTA）.     

Application of Rate Compatible Punctured Turbo Coded Hybrid ARQ to MC‐CDMA Mobile Radio

MC‐CDMA, a multicarrier (MC) modulation scheme based on code division multiple access (CDMA), is the most likely candidate for the next generation of mobile radio communications. The rate compatible punctured turbo (RCPT) coded hybrid automatic repeat request (HARQ) has been found to give improved throughput performance in a direct sequence (DS) CDMA system. However, the extent to which the RCPT HARQ improves the throughput performance of an MC‐CDMA system has not been fully understood. In this paper, we apply the RCPT HARQ to MC‐CDMA and evaluate by computer simulations its performance in a frequency selective Rayleigh fading channel. We found that the performance of RCPT HARQ MC‐CDMA is almost insensitive to channel characteristics. The performance can be drastically improved with receive diversity combined with space‐time transmit diversity. In addition, the comparison of RCPT HARQ MC‐CDMA, orthogonal frequency division multiplexing, and DS‐CDMA shows that under similar conditions the throughput of MC‐CDMA is the best in a frequency selective fading channel.     

Effect of Graded Dispersion of SiC Particles on Dielectric Behavior of SiC/Epoxy Composite

Silicon - Gradient structures mainly boost the dielectric and mechanical properties of composites. Herein, the fabrication of silicon carbide (SiC)/epoxy gradient composites via centrifugal casting...     

Pathways of nanotoxicity: Modes of detection,impact, and challenges

Nanotoxicology has become the subject of intense research for more than two decades. Thousands of articles have been published but the space in understanding the nanotoxicity mechanism and the assessment is still unclear. Recent researches clearly show potential benefits of nanomaterials (NMs) in diagnostics and treatment, targeted drug delivery, and tissue engineering owing to their excellent physicochemical properties. However, these NMs display hazardous health effect then to the greater part of the materials because of small size, large surface area-to-volume ratio, quantum size effects, and environmental factors. Nowadays, a large number of NMs are used in industrial products including several medical applications, consumer, and healthcare products. However, they came into the environment without any safety test. The measurement of toxicity level has become important because of increasing toxic effects on living organisms. New realistic mechanism-based strategies are still needed to determine the toxic effects of NMs. For the assessment of NMs toxicity, reliable and standardized procedures are necessary. This review article provides systematic studies on toxicity of NMs involving manufacturing, environmental factors, eco-toxic and genotoxic effects, some parameters which have been ignored of NMs versus their biological counterparts, cell heterogeneity, and their current challenges and future perspectives.     

Transport and Magneto-Transport Properties of Ru Doped Ln0.67Sr0.33MnO3 (Ln?=?La, Pr, and Nd)

The effect of Mn site doping by small amount Ru (5?%) on the transport and magneto-transport properties of the Ln_0.67Sr_0.33Mn_1?x Ru _x O₃ (where Ln?=?La, Pr, and Nd, x?=?0, 0.05) has been studied. Polycrystalline samples were synthesized by the conventional solid state reaction method. The samples of Pr_0.67Sr_0.33Mn_1?x Ru _x O₃ and Nd_0.67Sr_0.33Mn_1?x Ru _x O₃ have shown single phase with orthorhombic structure as well as La_0.67Sr_0.33Mn_1?x Ru _x O₃ has rhombohedral are revealed from XRD measurement. The temperature dependence of the resistivity is measured from 5 to 400?K. La_0.67Sr_0.33Mn_0.95Ru_0.05O₃ shows the metal?Cinsulator (M?CI) transition at 379?K while Pr_0.67Sr_0.33Mn_0.95Ru_0.05O₃ and Nd_0.67Sr_0.33Mn_0.95Ru_0.05O₃ have shown M?CI transition at 294 and 249?K, respectively. The magnetoresistance (MR) was measured with an applied magnetic field of 1, 3 and 5?T. Though the M?CI transition temperature decreases marginally, MR up to 70?% has been observed.