Heat and mass transfer and thermodynamic analysis of power-law fluid flow in a porous microchannel

Journal of Thermal Analysis and Calorimetry - Transfer of heat and mass and thermodynamic irreversibilities are investigated in a porous, parallel-plate microreactor in which the working fluid is...     

A novel magnetic nanocatalyst Fe3O4@PEG–Ni for the green synthesis of 2,3-dihydroquinazolin-4(1H)-ones

Ni-PEG (polyethylene glycol) complex supported on magnetic nanoparticle was created by grafting. The catalytic activity of Fe₃O₄@PEG–Ni was explored through one-pot green synthesis of 2,3-dihydroquinazolin-4(1H)-ones and used as an efficient and recoverable nanocatalyst. FT-IR, XRD, EDS, BET, TGA, VSM and SEM techniques were employed to specify the nanocatalyst. This heterogeneous nanocatalyst demonstrated acceptable recyclability and could be reused several times with no considerable loss of its catalytic activity.     

Numerical and artificial neural network modeling study on the first-law and second-law performance of a novel helical heat sink filled with water–silver nanofluid

Journal of Thermal Analysis and Calorimetry - This paper is devoted to studying the first-law and second-law performances of a novel helical heat sink (HS). The biologically synthesized...     

Poly(1,4-butyl-bis-vinylpyridinium) borohydride as a new stable and efficient reducing agent in organic synthesis

The unstable sodium borohydride is stabilized on modified poly(4-vinylpyridinium), and it is used as an efficient and regenerable polymer-supported borohydride reagent for the reduction of a variety of carbonyl compounds, such as aldehydes, ketones, α,β-unsaturated carbonyl compounds, α-diketones and acyloins, in good to excellent yields.     

Super-Earths: a new class of planetary bodies

Super-Earths, a class of planetary bodies with masses ranging from a few Earth-masses to slightly smaller than Uranus, have recently found a special place in exoplanetary science. Being slightly larger than a typical terrestrial planet, super-Earths may have physical and dynamical characteristics similar to those of Earth whereas unlike terrestrial planets, they are relatively easier to detect. Because of their sizes, super-Earths can maintain moderate atmospheres and possibly dynamic interiors with plate tectonics. They also seem to be more common around low-mass stars where the habitable zone is in closer distances. This article presents a review of the current state of research on super-Earths, and discusses the models of the formation, dynamical evolution, and possible habitability of these objects. Given the recent advances in detection techniques, the detectability of super-Earths is also discussed, and a review of the prospects of their detection in the habitable zones of low-mass stars is presented.     

Water Expandable Polystyrene-Organoclay Nanocomposites: Role of Clay and Its Dispersion State

A published process for preparing expandable polystyrene containing water as a blowing agent was applied to synthesize water expandable polystyrene-organoclay nanocomposites (WEPS-OCN). Organoclay was uniformly dispersed in styrene monomer. During suspension polymerization, water was trapped in the polystyrene (PS) matrix through the use of starch, ending up with spherical PS-organoclay beads. By selecting organoclays with various surfactants and modifier concentrations, different distribution states of nanoclay in the PS matrix, from cluster (poor dispersion) to either intercalated (limited dispersion) or exfoliated (full dispersion) were obtained. The incorporation of organoclay led to higher water content in the expandable beads. However, as expected, the flammability of the expanded product was increased with organoclay content. Furthermore, the results showed that the average unexpanded bead size, density of preexpanded beads, foam cell morphology, and flammability were directly influenced by the dispersion status of the organoclay. The best results were obtained when full dispersion (exfoliation) of nanoclay in PS matrix occurred.     

Application of nitrogen-rich porous organic polymer for the solid-phase synthesis of 2-amino-4H-benzo[b]pyran scaffolds using ball milling process

Molecular Diversity - This paper presents the efficient synthesis of 2-amino-4H-benzo[b]pyrans using mesoporous poly-melamine-formaldehyde as a polymeric heterogeneous catalyst. According to the...     

Analysis of unsteady mixed convection of Cu–water nanofluid in an oscillatory,lid-driven enclosure using lattice Boltzmann method

Journal of Thermal Analysis and Calorimetry - The unsteady physics of laminar mixed convection in a lid-driven enclosure filled with Cu–water nanofluid is numerically investigated. The top...     

Discovery of Quinazoline-2,4(1H,3H)-Dione Derivatives as Potential Antibacterial Agent: Design,Synthesis, and Their Antibacterial Activity

In this paper, we report on the design and synthesis of a novel series of quinazoline-2,4(1H,3H)-dione derivatives as fluoroquinolone-like inhibitors of bacterial gyrase and DNA topoisomerase IV to identify and develop antimicrobial agents to prevent bacterial resistance problems. Their structures were confirmed using spectroscopic analyses (IR, NMR, and EI-MS). The novel quinazoline-2,4(1H,3H)-dione derivatives were evaluated for their antimicrobial activities against Gram-positive and Gram-negative bacterial strains using the Agar well diffusion method to study the antimicrobial activities and compared them with the standard drugs. Most compounds displayed moderate activity. Among the tested compounds, the most promising compounds 13 and 15 provided broad bioactive spectrum against Gram-positive and Gram-negative strains compared to the standard drugs.