A Detailed Study on Internet Connectivity Schemes for Mobile ad Hoc Network

Wireless Personal Communications - Integration of Mobile ad hoc network (MANET) with the fixed Internet has paid immense attention in the field of heterogeneous networks. Such integration has many...     

Virtual grid-based rendezvous point and sojourn location selection for energy and delay efficient data acquisition in wireless sensor networks with mobile sink

Wireless Networks - Rendezvous points (RPs) based data acquisition methods are widely accepted as the solution for data acquisition delay/latency problem. In these methods, RPs are a subset of...     

AVDR: A Framework for Migration Policy to Handle DDoS Attacked VM in Cloud

Wireless Personal Communications - The recent trends of Distributed Denial of Service (DDoS) attacks in cloud computing have revealed a new menace of DDoS attacks called collateral damages on...     

Synthesis and characterization of highly transparent and hydrophobic fluorinated polyimides derived from perfluorodecylthio substituted diamine monomers

Two new perfluorodecylthio substituted aromatic diamines, namely 2,4‐diamino‐1‐(1H,1H,2H,2H‐perfluorodecathio)benzene (DAPFB) and 2,2'‐Bis((1H,1H,2H,2H‐perfluorodecyl)thio)[1,1'‐biphenyl]4,4'‐diamine (BPFBD) were synthesized and polycondensed with 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) to produce two new perfluorinated polyimides (PI2 and PI4). The chemical structures of these polyimides were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Two other polyimides (PI1 and PI3) were also synthesized from 6FDA and analogous perfluorodecylthio unsubstituted diamines to investigate the incorporation effect of perfluorodecylthio group on various physical and chemical properties of the synthesized PIs. Compared with PI1 and PI3, PI2 and PI4 exhibited improved solubility, optical transparency, and hydrophobicity, lower moisture absorption, dielectric constant, and thermo‐mechanical stabilities owing to the presence of the perfluorodecylthio side group in the polymer chain. Even though thermo‐mechanical properties of PI2 and PI4 ( : 413 and 404 °C, T_g: 220 and 209 °C, tensile strength of 101 and 76 MPa, tensile modulus of 1.7 and 1.5 GPa and elongation at break of 8 and 10%, respectively) were reduced in comparison to PI1 and PI3 but still were good enough for most of the practical applications. Most importantly, the presence of the perfluorodecylthio side group in BPFBD considerably reduced the dielectric constant of PI4 to 2.71 which was quite low as aromatic polyimide. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 479–488     

l-Proline-catalyzed one-pot expeditious synthesis of highly substituted pyridines at room temperature

Only 15 mol% of l-proline in ethanol proved to be a very efficient catalyst for the one-pot synthesis of a wide variety of highly substituted pyridines at room temperature. The methodology is mild, efficient, high yielding, and the products can be directly recrystallized from hot ethanol.