Development of Ag/TiO2NM-treated leathers with antibacterial activity for footwear industry

This work aims to contribute to the industrial development of safer and advanced leathers using nanomaterials (NMs) that are based in titanium oxide doped with silver (Ag-TiO2NMs). These NMs present an ecological alternative to volatile organic biocides and organic solvents, frequently used nowadays. Safe application of these NMs brings added value to footwear and leather products and reduces the bulk chemical wide pollution. These newly developed materials are expected to be useful for footwear manufacturing (for common or professional use) with advanced protection against bacteria and fungus, which are the most common cause of feet infections, for either common or professional use. Hence, the main aim of this work is the improvement of leather footwear in order to overcome the feet infections and ensure minimum risk of human skin penetration. In order to accomplish the main aim, the cytotoxicity, antimicrobial and self-cleaning properties of leather surface, treated with Ag-TiO2NMs by sputtering deposition were assessed. The Ag-TiO2 coatings were deposited onto leather substrates by DC-pulsed reactive magnetron sputtering using two targets, Ti and Ag, in an Ar + O2 atmosphere. Compositional analysis was achieved by X-ray energy dispersive spectrometry (EDX). Contact angle of the coatings was measured and the results show that with the introduction of silver in TiO2 microstructure promotea an increase in hydrophobicity. The antibacterial activity of the samples was assessed by agar diffusion method and the results point out to a silver antibacterial activity

Using Unity3D as an Elevator Simulation Tool

Simulations are used for finding answers to what-if scenarios prior to making decisions. Discrete event simulation (DES) tools are usually used for industrial processes. However, these tools require the creators of the simulation model to have highly specialized knowledge and they only rarely provide easily understandable graphic representations of the modelled situation. An elevator simulation model was created using an unusual approach: the simulation model was developed in Unity3D, an IDE intended for making computer games. The model was evaluated in terms of the accuracy of the results and of the suitability of using such a tool for creating an elevator simulation with a sequence dispatcher. The paper includes validation results and discusses the advantages, disadvantages and limits of such an approach. Although a DES tool would be better for the elevator itself, separate details of the simulation can be much more easily modelled in Unity3D. It can take into account 3D space (as opposed to 1D, which is usual for DESs), for example for finding probable paths of persons, calculating volumes or finding the right door opening times

Detection of an optical transient following the 13 March 2000 short/hard gamma-ray burst

We imaged the error box of a gamma-ray burst of the short (0.5 s), hard type (GRB 000313), with the BOOTES-1 experiment in southern Spain, starting 4 min after the gamma-ray event, in the I-band. A bright optical transient (OT 000313) with I = 9.4 +/- 0.1 was found in the BOOTES-1 image, close to the error box (3-sigma) provided by BATSE. Late time VRIK'-band deep observations failed to reveal an underlying host galaxy. If the OT 000313 is related to the short, hard GRB 000313, this would be the first optical counterpart ever found for this kind of events (all counterparts to date have been found for bursts of the long, soft type). The fact that only prompt optical emission has been detected (but no afterglow emission at all, as supported by theoretical models) might explain why no optical counterparts have ever been found for short, hard GRBs.This fact suggests that most short bursts might occur in a low-density medium and favours the models that relate them to binary mergers in very low-density enviroments.Comment: Revised version. Accepted for publication in Astronomy and Astrophysics Letters, 5 pages, 3 figure

Search for correlations between BATSE Gamma-Ray Bursts and Supernovae

We report on complex statistical research of space-time correlated supernovae and CGRO-BATSE gamma-ray bursts. We show that there exists a significantly higher abundanceof core-collapsesup ernovaeamong thecorre lated supernovae, but the subset of all correlated objects does not seem to be physically different from the whole set

Surface softening in metal-ceramic sliding contacts: An experimental and numerical investigation

This study investigates the tribolayer properties at the interface of ceramic/metal (i.e., WC/W) sliding contacts using various experimental approaches and classical atomistic simulations. Experimentally, nanoindentation and micropillar compression tests, as well as adhesion mapping by means of atomic force microscopy, are used to evaluate the strength of tungsten?carbon tribolayers. To capture the influence of environmental conditions, a detailed chemical and structural analysis is performed on the worn surfaces by means of XPS mapping and depth profiling along with transmission electron microscopy of the debris particles. Experimentally, the results indicate a decrease in hardness and modulus of the worn surface compared to the unworn one. Atomistic simulations of nanoindentation on deformed and undeformed specimens are used to probe the strength of the WC tribolayer and despite the fact that the simulations do not include oxygen, the simulations correlate well with the experiments on deformed and undeformed surfaces, where the difference in behavior is attributed to the bonding and structural differences of amorphous and crystalline W-C. Adhesion mapping indicates a decrease in surface adhesion, which based on chemical analysis is attributed to surface passivation

Spark plasma sintering of TiyNb1-yCxN1-x monolithic ceramics obtained by mechanically induced self-sustaining reaction

Nanometer-sized titanium-niobium carbonitride powders (TiyNb1-yCxN1-x) with different Ti/Nb atomic ratios were obtained by a mechanically induced self-sustaining reaction, and sintered by spark plasma sintering technique at 1500 degrees C for 1 min in a vacuum atmosphere. Mechanical properties such as hardness and Young's modulus were determined by nanoindentation technique and friction and wear coefficients assessed by ball-on-disk testing using alumina ball in dry sliding conditions. The fracture surface and wear tracks of samples were examined by scanning electron microscopy. Results showed that it is possible to obtain dense monolithic ceramics from the solid solution (TiyNb1-yCxN1-x) with good mechanical properties and excellent wear resistance. The optimum values of nanomechanical properties were found for the Ti0.3Nb0.7C0.5N0.5 ceramic composition, which exhibited a high hardness over 26.0 GPa and Young's modulus around 400 GPa. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.The authors would like to thank Dr. Emilio Rayon for performing the nanoindentation analysis in the Materials Technology institute (ITM) of the Polytechnic University of Valencia and to acknowledge the financial support received from Spanish Ministry of Science and Innovation for FPI grant (MAT2006-01783). This work was supported by the Spanish government under grant (MAT2010-17046), which is financed in part by the European Regional Development Fund of 2007-2013. E. Chicardi was supported by CSIC through a JAE-Pre grant, which is financed in part by the European Social Fund (ESF).Borrell Tomás, MA.; Salvador Moya, MD.; Garcia-Rocha, V.; Fernandez, A.; Chicardi, E.; Gotor, FJ. (2012). Spark plasma sintering of TiyNb1-yCxN1-x monolithic ceramics obtained by mechanically induced self-sustaining reaction. Materials Science and Engineering: A. 543:173-179. https://doi.org/10.1016/j.msea.2012.02.071S17317954