Strain rate effect on the mechanical behaviour of a textile reinforced cement composite

The static tensile behaviour of Textile Reinforced Cement Composites is known and can be modeled adequately. However, using these static material properties under dynamic loadings such as impact and seismic loadings, can cause over- or underestimation of the material due to effects of strain rate. This work focuses on the strain rate dependency of a specific textile reinforced cement composite under tensile loadings at strain rates equivalent to quasi static applications towards low velocity impacts. It was found that the main damage mechanisms of this material stay the same. However cracking of the cement matrix is delayed to higher stress levels

A two-stage ceramic tile grout sealing process using a high power diode laser Part I: Grout development and materials characteristics

Work has been conducted using a 60 W-cw high power diode laser (HPDL) in order to determine the feasibility and characteristics of sealing the void between adjoining ceramic tiles with a specially developed grout material having an impermeable enamel surface glaze. A two-stage process has been developed using a new grout material which consists of two distinct components: an amalgamated compound substrate and a glazed enamel surface; the amalgamated compound seal providing a tough, heat resistant bulk substrate, whilst the enamel provides an impervious surface. HPDL processing has resulted in crack free seals produced in normal atmospheric conditions. The basic process phenomena are investigated and the laser effects in terms of seal morphology, composition and microstructure are presented. Also, the resultant heat affects are analysed and described, as well as the effects of the shield gases, O2 and Ar, during laser processing. Tiles were successfully sealed with power densities as low as 500 W/cm2 and at rates up to 600 mm/min. Contact angle measurements revealed that due to the wettability characteristics of the amalgamated oxide compound grout (AOCG), laser surface treatment was necessary in order to alter the surface from a polycrystalline to a semi-amorphous structure, thus allowing the enamel to adhere. Bonding of the enamel to the AOCG and the ceramic tiles was identified as being principally due to van der Waals forces, and on a very small scale, some of the base AOCG material dissolving into the glaze

Optimization of electrocoagulation process to treat biologically pretreated bagasse effluent

The main objective of the present study was to investigate the efficiency of electrocoagulation process as a post-treatment to treat biologically pretreated bagasse effluent using iron electrodes. The removal of chemical oxygen demand (COD) and total suspended solids (TSS) were studied under different operating conditions such as amount of dilution, initial pH, applied current and electrolyte dose by using response surface methodology (RSM) coupled with four-factor three-level Box-Behnken experimental design (BBD). The experimental results were analyzed by Pareto analysis of variance (ANOVA) and second order polynomial mathematical models were developed with high correlation of efficiency (R2) for COD, TSS removal and electrical energy consumption (EEC). The individual and combined effect of variables on responses was studied using three dimensional response surface plots. Under the optimum operating conditions, such as amount of dilution at 30 %, initial pH of 6.5, applied current of 8 mA cm-2 and electrolyte dose of 740 mg l-1 shows the higher removal efficiency of COD (98 %) and TSS (93 %) with EEC of 2.40 Wh, which were confirmed by validation experiments

Global innovation generation and financial performance in business-to-business relationships: The case of cross-border alliances in the pharmaceutical industry

The past few decades have witnessed a significant increase in the number of cross-border strategic alliances among firms. We focus on the role of alliance expertise (alliance experience and diversity of partners) and alliance governance (horizontal vs. vertical alliances and joint venture vs. other alliances) in global innovation generation. We also examine the effect of these variables on the financial performance of the focal firm. The conceptual model is tested using an empirical analysis of cross-border alliances formed by U. S. pharmaceutical companies from 1985 to 2008. We find that while prior alliance experience has a positive association with global innovation generation, diversity of partners has a negative relationship. In addition, whether the alliance is horizontal or vertical has no bearing on the innovation generation, but joint ventures are associated with more global innovation generation than other types of alliances. Finally, as global innovation generation increases, financial performance increases up to a point but thereafter exhibits a negative relationship. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

A variationally consistent Streamline Upwind Petrov–Galerkin Smooth Particle Hydrodynamics algorithm for large strain solid dynamics

This paper presents a new Smooth Particle Hydrodynamics (SPH) computational framework for explicit fast solid dynamics. The proposed methodology explores the use of the Streamline Upwind Petrov–Galerkin (SUPG) stabilisation methodology as an alternative to the Jameson–Schmidt–Turkel (JST) stabilisation recently presented by the authors in Lee et al. (2016) in the context of a conservation law formulation of fast solid dynamics. The work introduced in this paper puts forward three advantageous features over the recent JST-SPH framework. First, the variationally consistent nature of the SUPG stabilisation allows for the introduction of a locally preserving angular momentum procedure which can be solved in a monolithic manner in conjunction with the rest of the system equations. This differs from the JST-SPH framework, where an a posteriori projection procedure was required to ensure global angular momentum preservation. Second, evaluation of expensive harmonic and bi-harmonic operators, necessary for the JST stabilisation, is circumvented in the new SUPG-SPH framework. Third, the SUPG-SPH framework is more accurate (for the same number of degrees of freedom) than its JST-SPH counterpart and its accuracy is comparable to that of the robust (but computationally more demanding) Petrov–Galerkin Finite Element Method (PG-FEM) technique explored by the authors in Lee et al. (2014), Gil et al. (2014,2016), Bonet et al. (2015), as shown in the numerical examples included. A series of numerical examples are analysed in order to benchmark and assess the robustness and effectiveness of the proposed algorithm. The resulting SUPG-SPH framework is therefore accurate, robust and computationally efficient, three key desired features that will allow the authors in forthcoming publications to explore its applicability in large scale simulations

Interpolating Coherent States for Heisenberg-Weyl and Single-Photon SU(1,1) Algebras

New quantal states which interpolate between the coherent states of the Heisenberg_Weyl and SU(1,1) algebras are introduced. The interpolating states are obtained as the coherent states of a closed and symmetric algebra which interpolates between the two algebras. The overcompleteness of the interpolating coherent states is established. Differential operator representations in suitable spaces of entire functions are given for the generators of the algebra. A nonsymmetric set of operators to realize the Heisenberg-Weyl algebra is provided and the relevant coherent states are studied.Comment: 13 pages nd 5 ps figure