Three-dimensional multiphase CFD modeling of thermal–hydraulic characteristics of nanofluid flow in helical microchannels

Journal of Thermal Analysis and Calorimetry - Forced convection heat transfer of two different types of water-based nanofluids (Al2O3, TiO2) was investigated numerically. In this numerical...     

About the Development and Dynamics of Microdischarges in Toluene-Containing Air

Plasma Chemistry and Plasma Processing - The development of microdischarges and the inception dynamics of subsequent microdischarges in an electrode arrangement consisting of a metal pin and a...     

D-glycopyranosyl phenylsulfones: Acylation of their lithiated anions and reductive desulfonylation of the resulting acylated sulfones. A synthesis of α-D-C-glycosides

The lithiated anion of 3,4,6-tri-O-t-butyldimethylsilyl-2-deoxy-α,β-D-glucopyronosyl phenylsulfone reacts with dimethylcarbonate and various phenyl esters to give stable acylated products. Subsequent reductive lithiation leads to enolates which undergo kinetic protonation to afford selectively α-D-C-glucosides.     

Total synthesis of calditol: structural clarification of this typical component of Archaea order Sulfolobales

The original structure of calditol--that is, an open-chain branched nonitol--has recently been questioned by various research groups and cyclopentane-based structures have been proposed. To unambiguously clear up this confusion, four isomeric cyclopentane candidates 26-29 have been synthesized. Of these, compound 27 was found to be fully identical to the natural product present in Sulfolobus solfataricus (A.T.C.C. 49155). The synthesis of 27 uses a samarium-diiodide-induced pinacolization reaction of the ketoaldehyde 15 as the critical step.     

Forecasting the thermal conductivity of a nanofluid using artificial neural networks

Journal of Thermal Analysis and Calorimetry - In this study, the influence of incorporating MWCNT on the thermal conductivity of paraffin was evaluated numerically. Input variables including mass...     

Synthesis of core–shell magnetic ion-imprinted polymer nanospheres for selective solid-phase extraction of Pb2+ from biological,food, and wastewater samples

Magnetic ion-imprinted polymer nanospheres, which have core–shell structures, have been synthesized as an adsorbent for extraction of Pb²⁺ from real samples prior to its flame atomic absorption spectrometric determination. The prepared adsorbent has been characterized using XRD, VSM, TEM, and FTIR measurements. The optimization results revealed that the adsorbent exhibited high selectivity toward Pb²⁺ over other cations such as Cu²⁺ and Zn²⁺. In addition, the removal efficiency of synthesized adsorbent was considerable (q_m?=?171.42?mg g^?1), its calibration curve was linear (0.5?850.0?ng mL^?1), and detection limit was 0.01?ng mL^?1. These results suggested that the prepared nanoadsorbent is an ideal candidate for solid-phase extraction of Pb²⁺ ions.     

Chemical clockwise tridifferentiation of alpha- and beta-cyclodextrins: bascule-bridge or deoxy-sugars strategies

The selective and efficient functionalisation of large concave molecules is a chemical challenge opening the door to various applications, such as artificial enzymes. We propose here a method, based on deprotection of benzylated cyclodextrins, to selectively access a variety of complex structures with two or three new different functionalities on the primary platform. Our strategy is based on a mechanistic hypothesis involving the approach of an aluminium reagent between the primary oxygen atom and the endocyclic one of the same sugar unit. Due to its cyclic directionality, a change in steric hindrance on a given position of the cyclodextrin has a different effect on the clockwise or the counterclockwise directions. This concept is illustrated and exploited in two complementary ways: deoxygenation of the primary position of two diametrically opposed sugars induces a debenzylation reaction on the neighbouring clockwise sugars of alpha- and beta-cyclodextrins. Reversible capping, or bascule-bridging, of the same pair of sugars has the same effect on the debenzylation of alpha-cyclodextrin, but induces an important change of the geometry of beta-cyclodextrin, hence allowing the selective access to yet another functionalisation pattern. A combined use of deoxygenation and bascule-bridging allows the access to an alpha-cyclodextrin with its three pairs of primary functions differentiated and ready for further modifications. Bascule-bridge or deoxy-sugars are two complementary means to operate steric decompression and induce selective reactions to efficiently access a number of new patterns of functionalities on concave molecules.