State equation of mineral sands

The pressure-volume analogy between compressible fluids and macroscopic sand bodies (Ivsic et al. in Phys A, 277:47–61, 2000) is further extended using quantitative determination of corresponding empirical constants based on adapted van der Waals state equation. The isothermal constants obtained by interpretation of triaxial sand tests at so called “critical state of sand” are clearly related to the universal ideal gas properties and molar properties of mineral sands. The corresponding constants for sand and gases or other volatile liquids have the same order of magnitude. The apparent bulk repulsion/attraction effects in sand bodies are also discussed.     

Effect of functionalized trititanate nanotubes on the properties of crosslinked cationic polymer nanocomposite

The synthesis and characterization of a crosslinked polymer nanocomposite containing titanium oxide nanotubes as filler are presented. First, the TiO₂ nanotubes were synthesized using a hydrothermal procedure and further functionalized using the organosilane reagent γ‐methacryloxypropyltrimethoxysilane. Subsequently, the modified nanotubes were incorporated into a polymer matrix using in situ polymerization of a mixture of monomer, crosslinker and initiator. Diverse characterization techniques were used at different stages of the synthesis, including transmission (TEM) and scanning electron microscopies, X‐ray diffraction (XRD), solid‐state ²⁹Si NMR and ¹³C NMR spectroscopy and nitrogen adsorption isotherms at 77 K. The as‐synthesized nanotubes correspond to the trititanate phase verified using XRD, and their presence within the nanocomposite was confirmed using TEM analysis. In addition, TiO₂ particles were detected on the surface of the nanocomposite. The nanocomposite exhibited a slight increase of Vickers microhardness while the water absorption decreased with oxide content attributed to trititanate nanotubes acting as multifunctional crosslinker.© 2015 Society of Chemical Industry     

Analysis of the biomineralization process on SWNT-COOH and F-SWNT films

In vitro biomineralization process was investigated on functionalized single wall nanotube (SWNT) films. The films were prepared by solvent casting method by using carboxylated and fluorinated nanotubes. SWNT films were characterized by means of electron microscopy, contact angle measurements and optical absorption. The in vitro assays were performed on cultured human alveolar bone-derived cells (HABDC) to determine the capabilities of carboxylated single-walled nanotubes (SWNTs-COOH) and fluorinated single-walled nanotubes (F-SWNTs) to promote the deposit of mineral-like tissue. The results showed that the cellular response of HABDC in secreting a mineralized extracellular matrix and their consequent mineralization is dependent on the degree of functionalization of the SWNTs. Differences were found related to the kind of sidewall functionalization. Both structures promoted hydroxyapatite formation, however, calcium uptake on SWNTs-COOH increased and it was related to crystal density. From our results, it is possible to infer that CNT functionalization opens a path to future developments in new bone graft materials and techniques.     

A methodology to forecast some attributes of an automatic storyteller’s outputs

ABSTRACT

This paper reports an extension of the program MEXICA, an automatic plot generator. The purpose of this project is to build a framework that permits studying the relations between MEXICA’s processes, its knowledge structures and the features of the produced narratives. We describe a methodology to analyse the features of the agent’s knowledge-base, to further establish correlations between such features and a set of general characteristics of the tales that they produce. Next, we make use of those correlations to forecast some properties of the future tales to be developed by different MEXICAs agents with different knowledge-bases. For this task, we introduce the S-graphs, representations of the similarity and organisation of the knowledge-structures. The results we obtained indicate that we are able to correctly forecast some of the features of tales to be produced; however, much more work is required.     

Structure,Mechanisms of Reaction,and Strength of an Alkali‐Activated Blast‐Furnace Slag

This research examines the chemical activation of blast‐furnace slag pastes with alkaline solutions by means of various characterization techniques. Pastes were activated using sodium silicate solutions with modulus (Ms) of 0, 1, 1.5, 2, and Na₂O at 5%, 10%, and 15%. Compressive strengths of up to 108 MPa were achieved for Ms = 1–1.5 after 720 d of curing at 20°C. The addition of Na₂O > 10% resulted in the formation of hydrotalcite and carbonated pastes with low compressive strength. X‐ray diffraction, microanalysis of outer products (OP), and nuclear magnetic resonance (NMR) results showed that the main reaction products in the activated cements with Ms = 1 and 5%Na₂O had an average ratio Ca/Si = 0.71–0.9 and consisted of a mixture of two kinds of C–S–H; one similar to a 9 Å tobermorite‐type calcium silicate hydrate (Ca₅Si₆O₁₆(OH)₂ and other amorphous related to a cross‐linked structure of C–N–(A)–S–H gel. Both were intermixed with hydrotalcite and cross‐linked structures of silica gel.     

The formation of a hydrothermal carbon coating on graphite microfiber felts for using as structured acid catalyst

A hydrothermal carbon layer has been coated on graphite felt using a carbohydrate solution (glucose, sucrose or starch) as precursor. The coating is uniform in thickness and coverage, and exhibits excellent adhesion to the substrate. It is highly hydrophilic, very accessible to reactants and the thickness can be tuned by the synthesis conditions. The coating was functionalized with sulfonic acid groups and its morphology and surface chemistry characterized by SEM, TPO-MS, IR-spectroscopy and XPS. The sulfonated material has been tested in the esterification of palmitic acid with methanol exhibiting significant activity and stability.     

Morphological Connected Filtering on Viscous Lattices

This paper deals with the notion of connectivity in viscous lattices. In particular, a new family of morphological connected filters, called connected viscous filters is proposed. Connected viscous filters are completely determined by two criteria: size parameter and connectivity. The connection of these filters is defined on viscous lattices in such a way that they verify several properties of the traditionally known filters by reconstruction. Moreover, reconstruction algorithms used to implement filters by reconstruction can also be employed to implement these new filters. We also show that connected viscous filters have a behavior similar to filters with reconstruction criteria. The interest of these new connected filters is illustrated with different examples.     

Metal ion extraction behavior of poly([2(methacryloyloxy)ethyl]trimethylammonium chloride-co-acrylic acid) resin

SUMMARY The crosslinked poly([2-(methacryloyloxy)ethyl]trimethyl ammonium chloride-co-acrylic acid) was tested as adsorbent for Cd(II), Hg(II), Zn(II), Pb(II), Cr(III), and U(VI) by batch equilibrium procedure. At pH 5.0 the adsorbent retained 74% (1.865 meq/g) of U(VI) with a maximum capacity of load of 2.7 meq/g (108 mg/g). The resin-U(VI) equilibrium was achieved around of 1 h which is considered adequate for a heterogeneous reaction. It showed a high selectivity for U(VI) respect to all the other metal ions both from competitive and non-competitive conditions. The recovery of the resin was over 65% by H₂SO₄ and Na₂CO₃. Received: 5 April 1999/Revised version: 14 July 1999/Accepted: 27 July 1999     

Crosslinking of poly(vinyl acetate) nanolatices by gamma and UV radiation

Poly(vinyl acetate) PVAc, in nanolatices with 10% polymer content, prepared by microemulsion polymerization was crosslinked by gamma and UV radiation. PVAc colloidal nanoparticles (average diameter, Dp = 58 nm) had M_w = 562,000 g/mol and about 95% conversions. PVAc nanolatices irradiated by gamma rays (1–13 kGy) at room temperature without crosslinking agent and by UV light (30–300 s exposure times) in the presence of divinylbenzene and allyl methacrylate showed crosslinking of up to 96% (high gel content), Dp < 100 nm and did not degrade as shown by FTIR spectroscopy. DSC and TGA characterization of irradiated PVAc samples indicated that T_g temperatures increased from 28°C for PVAc to 42°C and 39°C for UV and gamma rays crosslinked PVAc, respectively, whereas 10% weight losses occurred at 261°C for uncrosslinked PVAc and at 320 and 313°C for UV and gamma rays crosslinked PVAc. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012