Extracting spectral density function of a binary composite without a-priori assumption

The spectral representation separates the contributions of geometrical arrangement (topology) and intrinsic constituent properties in a composite. The aim of paper is to present a numerical algorithm based on the Monte Carlo integration and contrainted-least-squares methods to resolve the spectral density function for a given system. The numerical method is verified by comparing the results with those of Maxwell-Garnett effective permittivity expression. Later, it is applied to a well-studied rock-and-brine system to instruct its utility. The presented method yields significant microstructural information in improving our understanding how microstructure influences the macroscopic behaviour of composites without any intricate mathematics.Comment: 4 pages, 5 figures and 1 tabl

Preliminary assessment of microfibres amount in textile wastewater

Textile wastewater is a complex mixture of inorganic compounds, polymers, organic products, dyes, and microfibers (MFs), including microplastics (MPs) and natural fibers. The treatment of textile wastewater, which contains a significant share of MFs, is of great importance to prevent the release of MPs in the environment. MPs analysis requires multiple phases of pretreatment (to eliminate the organic compounds), separation of the MFs from the water, and identification of the MPs among the MFs.This work presents the preliminary results of a research aimed at exploring two issues. Firstly, the pretreatment (through Fenton, H2O2, HCl, KOH and NaOH, applied at 25 °C for 5 days and 60 °C for 6 hours) of artificial textile wastewater, evaluating the effect of the different conditions on the MFs and the MPs. Secondly, the separation of MFs from a real textile wastewater sample through different processes (centrifugation, sink-float & filtration, filtration). The results of the pretreatment tests revealed Fenton, HCl, and H2O2 at 25 °C for 5 days as the best performing chemicals and conditions. Considering the results of the separation tests, filtration gave back the best removal of the MFs from wastewater compared to centrifugation and sink-float and filtration, which left some MFs in the supernatant/float and in the sediment/sink. In conclusion, these preliminary results may be useful to further explore the detection of MFs and MPs in textile wastewater

2-[(1E)-({[(Benzylsulfanyl)methanethioyl]amino}- imino)methyl]-6-methoxyphenol: crystal structure and Hirshfeld surface analysis

The title di­thio­carbazate ester, C16H16N2O2S2, comprises two almost planar residues, i.e. the phenyl ring and the remaining 14 non-H atoms (r.m.s. deviation = 0.0410 Å). These are orientated perpendicularly, forming a dihedral angle of 82.72 (5)°. An intra­molecular hy­droxy-O—H⋯N(imine) hydrogen bond, leading to an S(6) loop, is noted. An analysis of the geometric parameters is consistent with the mol­ecule existing as the thione tautomer, and the conformation about the C=N bond is E. The thione S and imine H atoms lie to the same side of the mol­ecule, facilitating the formation of inter­molecular N—H⋯S hydrogen bonds leading to eight-membered {⋯HNCS}2 synthons in the crystal. These aggregates are connected by phenyl-C—H⋯O(hy­droxy) inter­actions into a supra­molecular layer in the bc plane; these stack with no directional inter­actions between them. An analysis of the Hirshfeld surface confirms the nature of the inter­molecular inter­actions

Crystal structure of 2-((1E)-{2-[bis(2-methylbenzylsulfanyl) methylidene]-hydrazin-1-ylidene}methyl)-6-methoxy-phenol

We thank the Department of Chemistry, Universiti Putra Malaysia for facilities. This research was funded by Universiti Putra Malaysia (UPM) and the Malaysian Government under the Geran UPM Scheme (RUGS No. IBT/2013/9419400), the Malaysian Fundamental Research Grant Scheme (FRGS No.01–02-13–1344FR) and the ScienceFund under the Ministry of Science, Technology and Innovation (MOSTI 06–01-04-SF1810). ENMY wishes to thank UPM for the award of a Graduate Research Fellowship.Peer reviewedPublisher PD

Numerical calculations of effective elastic properties of two cellular structures

Young's moduli of regular two-dimensional truss-like and eye-shape-like structures are simulated by using the finite element method. The structures are the idealizations of soft polymeric materials used in the electret applications. In the simulations size of the representative smallest units are varied, which changes the dimensions of the cell-walls in the structures. A power-law expression with a quadratic as the exponential term is proposed for the effective Young's moduli of the systems as a function of the solid volume fraction. The data is divided into three regions with respect to the volume fraction; low, intermediate and high concentrations. The parameters of the proposed power-law expression in each region are later represented as a function of the structural parameters, unit-cell dimensions. The presented expression can be used to predict structure/property relationship in materials with similar cellular structures. It is observed that the structures with volume fractions of solid higher than 0.15 exhibit the importance of the cell-wall thickness contribution in the elastic properties. The cell-wall thickness is the most significant factor to predict the effective Young's modulus of regular cellular structures at high volume fractions of solid. At lower concentrations of solid, eye-like structure yields lower Young's modulus than the truss-like structure with the similar anisotropy. Comparison of the numerical results with those of experimental data of poly(propylene) show good aggreement regarding the influence of cell-wall thickness on elastic properties of thin cellular films.Comment: 7 figures and 2 table

Bis{4-methylbenzyl 2-[4-(propan-2-yl)benzylidene]hydrazinecarbodithioato-κ2N2,S}nickel(II): crystal structure and Hirshfeld surface analysis

The complete molecule of the title hydrazine carbodithioate complex, [Ni(C19H21N2S2)2], is generated by the application of a centre of inversion. The NiII atom is N,S-chelated by two hydrazinecarbodithioate ligands, which provide a trans-N2S2 donor set that defines a distorted square-planar geometry. The conformation of the five-membered chelate ring is an envelope with the NiII atom being the flap atom. In the crystal, p-tolyl-C—H...π(benzene-iPr), iPr-C—H...π(p-tolyl) and π–π interactions [between p-tolyl rings with inter-centroid distance = 3.8051 (12) Å] help to consolidate the three-dimensional architecture. The analysis of the Hirshfeld surface confirms the importance of H-atom contacts in establishing the packing

Signs of low frequency dispersions in disordered binary dielectric mixtures (50-50)

Dielectric relaxation in disordered dielectric mixtures are presented by emphasizing the interfacial polarization. The obtained results coincide with and cause confusion with those of the low frequency dispersion behavior. The considered systems are composed of two phases on two-dimensional square and triangular topological networks. We use the finite element method to calculate the effective dielectric permittivities of randomly generated structures. The dielectric relaxation phenomena together with the dielectric permittivity values at constant frequencies are investigated, and significant differences of the square and triangular topologies are observed. The frequency dependent properties of some of the generated structures are examined. We conclude that the topological disorder may lead to the normal or anomalous low frequency dispersion if the electrical properties of the phases are chosen properly, such that for ``slightly'' {\em reciprocal mixture}--when $\sigma_1\gg\sigma_2$, and $\epsilon_1<\epsilon_2$--normal, and while for ``extreme'' {\em reciprocal mixture}--when $\sigma_1\gg\sigma_2$, and $\epsilon_1\ll\epsilon_2$--anomalous low frequency dispersions are obtained. Finally, comparison with experimental data indicates that one can obtain valuable information from simulations when the material properties of the constituents are not available and of importance.Comment: 13 pages, 7 figure

A cinnamaldehyde Schiff base ofS-(4-methylbenzyl) dithiocarbazate: crystal structure, Hirshfeld surface analysis and computational study

The title dithiocarbazate ester (I), C18H18N2S2 [systematic name: (E)-4-methylbenzyl 2-[(E)-3-phenylallylidene]hydrazinecarbodithioate, comprises an almost planar central CN2S2 residue [r.m.s. deviation = 0.0131 Å]. The methylene(tolyl-4) group forms a dihedral angle of 72.25 (4)° with the best plane through the remaining non-hydrogen atoms [r.m.s. deviation = 0.0586 Å] so the molecule approximates mirror symmetry with the 4-tolyl group bisected by the plane. The configuration about both double bonds in the N—N=C—C=C chain is E; the chain has an all trans conformation. In the crystal, eight-membered centrosymmetric thioamide synthons, {...HNCS}2, are formed via N—H...S(thione) hydrogen bonds. Connections between the dimers via C—H...π interactions lead to a three-dimensional architecture. A Hirshfeld surface analysis shows that (I) possesses an interaction profile similar to that of a closely related analogue with an S-bound benzyl substituent, (II). Computational chemistry indicates the dimeric species of (II) connected via N—H...S hydrogen bonds is about 0.94 kcal mol−1 more stable than that in (I)

Synthesis, characterisation and structure determination of 3-[(1Z)-{2-[bis({[(2-methylphenyl)methyl]sulfanyl})methylidene]hydrazin-1-ylidene}methyl]benzene-1,2-diol

A light-yellow crystalline product (1), which was isolated after one week from the filtrate of the reaction between S-2-methylbenzyldithiocarbazate and 2,3-dihydroxybenzaldehyde, was characterised by single crystal X-ray diffraction, FTIR and NMR spectroscopic analyses. The experimental molecular structure of 1 has been established by X-ray crystallography and showed, to a first approximation, a planar C2N2S2 + dihydroxyphenyl region that has an almost orthogonal relationship to the rings of the pendant S-bound benzyl groups. This structure has been verified via density functional theory calculations using the B3LYP/6311G(d,p) level of theory. The molecular packing featured linear supramolecular chains along the b-axis sustained by tolyl-C–H…N(imine) and tolyl-C–H…π(tolyl) interactions; the importance of these contacts is indicated by a Hirshfeld surface analysis