A study on the mechanical strength of Fe2O3/Cr2O3/CuO catalyst for high temperature water gas shift reaction

Journal of Porous Materials - The present study aims to investigate the effects of iron (hydr)oxide phases formed during precipitation and the addition of different binders on the mechanical and...     

Highly efficient synthesis of coumarin derivatives in the presence of H14[NaP5W30O110] as a green and reusable catalyst

A variety of heteropolyanions including: Keggin, Dawson, Preyssler, mixed addenda and sandwich types, catalyzed the formation of 4-methylnaphtho-(1,2-b)-pyran-2-one (coumarin) from the condensation of α-naphthol and ethylacetoacetate in a solvent free system and under heating conditions. Our data vividly indicate that sodium30–tungsto pentaphosphate, [NaP₅W₃₀O₁₁₀]¹⁴⁻, which so-called Preyssler’s anion, with high hydrolytic (pH 0–12) and thermal stability is the catalyst of choice. This catalyst catalyzed the synthesis of other coumarin derivatives in high yields and good selectivity.     

Wireless Information and Power Transfer in Single User OFDM Systems

Wireless Personal Communications - In this article, OFDM-based single-user simultaneous wireless information and power transfer (SWIPT) system for power splitting (PS) and time switching (TS) plans...     

Highly efficient synthesis of benzopyranopyridines via ZrP2O7 nanoparticles catalyzed multicomponent reactions of salicylaldehydes with malononitrile and thiols

ZrP₂O₇ nanoparticles as an efficient catalyst have been used for the preparation of benzopyrano[2,3-b]pyridines from the four-component condensation reaction of salicylalde-hydes, thiols, and 2 equiv. of malononitrile under reflux conditions in ethanol in excellent yields and short reaction times.     

Nickel‐Catalyzed Reductive Benzylation of Aldehydes with Benzyl Halides and Pseudohalides

The reductive benzylation of aromatic and aliphatic aldehydes with benzylic halides is reported using a nickel/zinc catalyst system. In addition to benzylic halides, the first report on the addition of benzylic triflates, acetates, tosylates and tritylates to aldehydes is also presented. By this new method a range of alcohols was synthesized efficiently from aldehydes and benzylic substrates at room temperature in moderate to high yields. The mild reaction conditions and good functional group tolerance make this nickel‐catalyzed process synthetically useful for the synthesis of diverse benzylic alcohols.

     

Effect of ionic strength on the reactivity ratios of acrylamide/acrylic acid (sodium acrylate) copolymerization

The ionic strength (IS) of polyelectrolyte solutions plays an important role in influencing reaction kinetics. The largely unstudied effect of IS on monomer reactivity ratios and copolymerization rates of acrylamide (AAm) and acrylic acid (AAc), in the form of sodium acrylate (NaAc), is investigated. Salt addition affects the nature of overall charges of the polyelectrolyte solution and diminishes the electrostatic repulsions between reacting chains. Therefore, changing the IS of the solution by incorporating salts affect not only the point estimates of the monomer reactivity ratios but also the overall behavior of the copolymerization (with a transition to azeotropic behavior). Experimental results on copolymerization rates confirm the observed trends in reactivity ratio behavior. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40949.     

Investigation on Microstructure,Wear Behavior and Microhardness of Al−Si/SiC Nanocomposite

Aluminum matrix nano-composites have been widely used in various fields such as aerospace, automobile, and packing industries. In this study, the effect of nano-SiC content on the microst-ructure, wear resistance and micro-hardness of Al–Si/SiC nano-composite was investigated. In this regard, Al–Si matrix was reinforced by different amounts of nano-SiC: 0, 0.5, 1, 1.5, 3, 5, 10 wt %. The results showed that with increasing the nano-SiC weight ratio, nano-particles are agglomerated and unsuitable sintering increases the porosity, as pores and cavities. For more than 1.5% weight ratio of nano-SiC in the matrix, the wear resistance and the micro-hardness decreased. The results of the wear test, scanning electron microscopy, energy dispersive X-ray spectroscopy and worn surfaces showed that the dominant wear mechanism is controlled by nano-SiC contents. This study indicated that with adding nano-SiC particles more than the optimal content, wear resistance and micro-hardness of Al–Si/SiC nano-composite increased more than twice.     

An Accurate Automatic Quality-Factor Tuning Scheme for Second-Order LC Filters

This paper presents a scheme to accurately tune the quality factor of second-order LC bandpass filters. The information of the magnitude response at the center and one of the cutoff frequencies is used to tune both the amplitude and the quality factor of the filter using two independent yet interacting loops. Furthermore, the synergic interaction between the loops makes the proposed scheme stable and insensitive to the mismatch between the input amplitudes. A chip prototype was implemented in a 0.35-mum CMOS process and consumes 4.3 mA from a single 1.3-V supply. Measurement results show that at 1.97 GHz the quality factor is tunable from 60 to 220 while the amplitude is tunable between -15 and 0 dBm with worst case quality factor and amplitude tuning accuracies of 10% and 7%, respectively