Modeling of Hysteretic Behavior of Soil–Water Retention Curves Using an Original Pore Network Model

Soil–water retention curve (SRWC), also called soil moisture characteristic, is used for simulation models of soil water storage or soil aggregate stability. The present study addresses the modeling of SRWC with particular attention paid to hysteresis effects of water filling and draining the pores attributed to ink-bottle effects. For that purpose, an idealized pore size distribution previously developed for predicting water sorption isotherms on cementitious materials, and which can consider the double porosity structure of soils, is used. The input data of the model are assessed only from mercury intrusion porosimetry tests (MIP) and from grain size distribution (GSD). The hysteretic behavior of SRWC is reproduced in a satisfactory way. The model can also predict the specific surface area.

     

Can a Procedure for the Growth of Single-layer Graphene on Copper be used in Different Chemical Vapor Deposition Reactors?

In the last decade, catalytic chemical vapor deposition (CVD) has been intensively explored for the growth of single-layer graphene (SLG). Despite the scattering of guidelines and procedures, variables such as the surface texture/chemistry of catalyst metal foils, carbon feedstock, and growth process parameters have been well-scrutinized. Still, questions remain on how best to standardize the growth procedure. The possible correlation of procedures between different CVD setups is an example. Here, two thermal CVD reactors were explored to grow graphene on Cu foil. The design of these setups was entirely distinct, one being a “showerhead” cold-wall type, whereas the other represented the popular “tubular” hot-wall type. Upon standardizing the Cu foil surface, it was possible to develop a procedure for cm²-scale SLG growth that differed only by the carrier gas flow rate used in the two reactors.     

Elucidating the intermolecular hydrogen bonding interaction of proline with amides—quantum chemical calculations

Structural Chemistry - The hydrogen-bonded complexes formed between proline and amides have been investigated completely by the use of computational methods such as Atoms In Molecules (AIM),...     

Convex fuzzy mapping with differentiability and its application in fuzzy optimization

The concepts of differentiability, convexity, generalized convexity and minimization of a fuzzy mapping are known in the literature. The purpose of this present paper is to extend and generalize these concepts to fuzzy mappings of several variables using Buckley–Feuring approach for fuzzy differentiation and derive Karush–Kuhn–Tucker condition for the constrained fuzzy minimization problem.     

Unprecedented Transformation of Thioglycosides to Their Corresponding 1‐O‐Acetates in the Presence of HClO4‐SiO2 §

An unprecedented conversion of thioalkyl/aryl glycoside to the corresponding 1‐O‐acetates has been described using acetic anhydride and HClO₄‐SiO₂ at rt. Although this transformation does not play an important role in the oligosaccharide synthesis in comparison to its reverse transformation, this gives useful information in selecting the reaction condition for the synthesis of oligosaccharides. The yields were excellent in all cases.     

Correlation between the cross-linking and degradation activation energy of cotton fabric treated with chitosan kinetic study by ‘model-free’ multiple heating rate methods

Journal of Thermal Analysis and Calorimetry - The different concentrations of chitosan were applied on cotton fabrics using glutaraldehyde as a cross-linking agent. The fabric samples were...     

The versatile,functional polyether,polyepichlorohydrin: History,synthesis, and applications

Polyepichlorohydrin (PECH) is a functional polyether first synthesized in the 1950's by the catalytic ring opening polymerization of epichlorohydrin (ECH), its inexpensive epoxide pre-cursor. PECH elastomers are used in diverse commercial applications due to their unique combination of properties including low temperature flexibility and heat and oil resistance. PECH holds an interesting place in polymer history as its synthesis led to the discovery of highly effective aluminum-based catalysts for epoxide polymerizations and a new class of high molecular weight polyether elastomers by an exceptional polymer chemist, Edwin J. Vandenberg. ECH is an ideal feedstock for polymer materials as it is functional, inexpensive, and produced through environmentally friendly means. However, due to the alkyl chloride pendant, polymerizations involving ECH are difficult and limited synthetic advancement has occurred until very recently. This focused review will discuss modern polymerization methods involving ECH while giving a historical perspective on the evolution of these techniques. We will also review applications of ECH-based polymers and discuss the future development of these materials. We hope to convince the reader to explore ECH-based materials in their own work.     

Mild and efficient method for the cleavage of benzylidene acetals using HClO4-SiO2 and direct conversion of acetals to acetates

HClO₄-SiO₂ has been used successfully for the deprotection of benzylidene acetals and the direct conversion of benzylidene acetals to the corresponding di-O-acetates. The reactions are very fast and yields are excellent.     

Comparison of hydrogen- and halogen-bonding interactions in the complexes of the substituted carbonyl compounds with hypohalous acids and monohaloamines

Structural Chemistry - An ab initio study of the complexes formed by hypohalous acids and monohaloamines (designated as HAX where A = O or NH and X = Cl, Br, or I) with RCHO (R = H, CH3, OCH3, and...