Characterization of Polyacrylonitrile Nanocomposites by Reinforcement of Functionalized Single-Walled Carbon Nanotubes

Polyacrylonitrile/functionalized single-walled carbon nanotubes (PAN/f-SWCNTs) nanocomposites were synthesized by an emulsifier-free in situ polymerization process. Interaction of polyacrylonitrile with functionalized single-walled carbon nanotubes was evidenced by ultraviolet-visible and Fourier transforms infrared spectroscopy. The structure and morphology of nanocomposites were characterized by X-ray diffraction, field emission scanning electron microscopy and high resolution transmission electron microscopy. Electrical conductivity was found to be increased by addition of f-SWCNTs. Thermogravimetric analysis study of PAN/f-SWCNT nanocomposites show more thermal resistance compared to the virgin PAN. The oxygen barrier property of PAN/f-SWCNT nanocomposites was reduced by eight times with increasing f-SWCNTs proportions.     

Effect of Ni<Superscript>2+</Superscript>, V<Superscript>4+</Superscript> and Mo<Superscript>6+</Superscript> concentration on iron oxidation by <Emphasis Type="Italic">Acidithiobacillus ferrooxidans</Emphasis>

The ferrous oxidation ability of Acidithiobacillus ferrooxidans was studied in the presence of Ni²⁺, V⁴⁺ and Mo⁶⁺ in 9 K media in order to implement the culture in the bioleaching of spent catalyst. The rate of iron oxidation decreased with increasing concentration of metal ions, but the rate of inhibition was metal-ion dependent. The tolerance limit was critical at a concentration of 25 g/L Ni²⁺, 5 g/L V⁴⁺ and 0.03 g/L Mo⁶⁺. The growth rate of microorganisms was negligible at concentrations of 6 g/L V⁴⁺ and 0.04 g/L Mo⁶⁺. Levels and degree of toxicity of these ions have been quantified in terms of a toxicity index (TI). The toxicity order of metal ions was found to be Mo⁶⁺>V⁴⁺>Ni²⁺. The significance and relevance of multi-metal ion tolerance in Acidithiobacillus ferrooxidans has been highlighted with respect to bioleaching of spent refinery catalyst.     

Nano-octopus: a new form of branching carbon nanofiber

A new multibranched octopus-type structure of carbon nanofibers is synthesized from a natural precursor, camphor, by a thermal chemical vapor deposition technique. An alloy of Cu:Ni catalyst is prepared by electrochemically coating nickel on a copper sheet, with nickel sulfate as an electrolyte, and heating that nickel-coated copper sheet to a higher temperature. Deposition of carbon on these substrates leads to the formation of a branched nanostructure in the temperature range of 923 K to 1023 K. The fiber diameter increases from 30 nm to 250 nm with increasing pyrolysis temperature. Detailed morphology and the internal structure of these fibers are studied by scanning and transmission electron microscopy.     

Ethical Issues in Empirical Software Engineering: The Limits of Policy

Empirical studies in software engineering can involve a variety of organizations, each with their own set of policies and procedures geared at safeguarding the interests and responsibilities of the researchers, students, the collaborating company, the university, and possibly national funding agencies like the National Science Foundation and the National Institute of Health. Each of these organizations have differing goals for participating in these studies and bring widely different cultures and expectations to the table. While policies, procedures, contracts, and agreements set expectations, they by themselves cannot ensure ethical behavior. This position paper describes some of the common approaches to encourage ethical behavior and their limits for enforcing ethical behavior.     

Comment on `Nonplanar VLSI arrays with high fault-tolerancecapabilities'

In the above-named work (see ibid., vol.38, p.51-7, April 1989), S. Lafiti and A. El-Amawy apply, in a straightforward manner, the method developed by A.D. Singh (1985) to calculate lower bounds for the yield of nonplanar interstitial redundancy topologies of processor arrays with spare processors. In their introduction, they claim that the models suggested by I. Koren and D.K. Pradhan (1987) are highly theoretical since the number of states in the Markov model might be very large and the determination of the transition rates might be intractable. They add that applying some empirical rules, as suggested by Koren and Pradhan (1987), can lead to unrealistic results and may require a large number of computations. They also claim that the model of Koren and Pradhan does not suggest an algorithm to replace faulty elements. They conclude that a simpler model, like the one proposed by Singh, is needed for calculating the yield of fault-tolerant processor arrays. In the present comment, Koren and Pradhan respond to the above comments and attempt to clarify the differences between their yield analysis and that of Singh     

Vibrational study of TlH2AsO4, TlH2-PO4 and their deuterated analogues

The Raman and infrared spectra of polycrystalline samples TlH₂AsO₄, TlD₂AsO₄, TlH₂PO₄ and TlD₂PO₄ have been investigated at 300 K in the frequency ranges 0 to 4000 and 200 to 4000cm^–1 respectively. The assignment of lattice, internal, and OH group vibrations has been approximated in terms of symmetry species. Although all the vibrations follow more or less the space group symmetry, the internal vibrations do not completely fulfill the requirements of the symmetry rule. The isotope effect was observed prominently on both compounds in Raman and infrared spectra. An attempt has been made to assign and explain the results.     

Procedures: Do we really want to know them? An examination of the effects of procedural justice on self-esteem.

This study examined the effects of procedural justice on state-dependent self-esteem using the group-value model and attribution theory to present competing theoretical perspectives. The group-value model predicts a positive relationship between self-esteem and fair procedures. In contrast, attribution theory suggests procedural fairness interacts with outcome favorability to influence self-esteem. Thus, fair procedures will result in higher self-esteem ratings than unfair procedures when the outcome is positive but will result in lower self-esteem ratings than unfair procedures when the outcome is negative. The results of a laboratory and field study provide converging evidence to support the attribution theory predictions. The results of a 2nd laboratory study suggest that self-esteem is influenced by outcome expectancies, not actual outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Novel Low-Temperature Synthesis of Nanosized NiZn Ferrite

Nanosized NiZn ferrite powder is synthesized by a low-temperature method, using a unique combination of citric acid and glycine. An appropriate molar ratio of both citric acid and glycine offers a low-temperature synthetic route by incorporating the complexation behavior of citric acid and the combustion nature of glycine. Thermal decomposition/controlled autocatalytic combustion of the composite gel occurs at a low temperature of around 175°C, with the evolution of a large amount of gases. Transmission electron microscopic studies showed that the average particle size of the ferrite obtained is ∼2.5 nm, with a narrow size distribution. Uniformly distributed fine-grained microstructure with low porosity is obtained for a sample sintered at 1000°C.     

Epoxidation of Canola Oil with Hydrogen Peroxide Catalyzed by Acidic Ion Exchange Resin

Canola oil with an iodine value of 112/100 g, and containing 60% oleic acid and 20% linoleic acid, was epoxidised using a peroxyacid generated in situ from hydrogen peroxide and a carboxylic acid (acetic or formic acid) in the presence of an acidic ion exchange resin (AIER), Amberlite IR 120H. Acetic acid was found to be a better oxygen carrier than formic acid, as it produced about 10% more conversion of ethylenic unsaturation to oxirane than that produced by formic acid under otherwise identical conditions. A detailed process developmental study was then performed with the acetic acid/AIER combination. The parameters optimised were temperature (65 °C), acetic acid to ethylenic unsaturation molar ratio (0.5), hydrogen peroxide to ethylenic unsaturation molar ratio (1.5), and AIER loading (22%). An iodine conversion of 88.4% and a relative conversion to oxirane of 90% were obtained at the optimum reaction conditions. The heterogeneous catalyst, AIER, was found to be reusable and exhibited a negligible loss in activity.