Synthesis and characterization of fire resistance polymeric coating solution for carbon-blended aluminized (E-glass-based) and non-aluminized fabric

Abstract

In this study, we report the development and characterization of fire-resistant non-intumescent polymeric resin for aluminized (E-glass-based) and non-aluminized (basofil/nomex/carbon-based) firefighting suit fabrics. The prospective coating resin is synthesized via two-step polymerization of polyimide using dimethylacetamide (DMAc) as a common solvent. 3-Aminopropyltriethoxysilane (APTES) is used as a coupling agent and is added just before coating. All the coating samples are prepared by hand layup technique and are allowed to cure (known as imidization) under the oven with increasing the temperature step-by-step from 80 to 350?°C. The imidization of coating resin is confirmed by FT-IR spectra analysis. Furthermore, all the samples are characterized with flammability, adhesion, thermal protective index, heat char and ignition, and thermal shrinkage as per BS 3120, MIL-C-29143, BS 3791, D-5537, and NFPA 1976 standards, respectively. The observed results confirmed that the prospective resin could be a better choice as fire-resistant coating for carbon-blended aluminized and/ non-aluminized fabric.     

Comparative study of the determination of platinum by extraction with Cyanex 923 and Cyanex 471X from bromide media

The extraction equilibrium study of Pt(IV) was carried out with Cyanex 923 and Cyanex 471X in toluene from hydrobromic acid media to investigate their extraction capacity, since they have different donor atoms, ‘O’ and ‘S’. Their distribution equilibria were studied as a function of extractant concentration, diluents, hydrobromic acid concentration and the effect of temperature on extraction. Pt(IV) was quantitatively extracted with 0.1 mol dm^?3 Cyanex 923 in toluene from 5.0–8.0 mol dm^?3 HBr media and was stripped with 4.0 mol dm^?3 perchloric acid. However it was also quantitatively extracted with 0.1 mol dm^?3 Cyanex 471X (with 0.1 mol dm^?3SnCl₂) in toluene from 6.0–8.0 mol dm^?3 HBr media and was stripped with 1.0 mol dm^?3 stabilized sodium thiosulfate solution at pH 9.0. The slope analysis method indicated metal complex species of 1:1 for Pt(IV) with Cyanex 923 and Cyanex 471X in toluene from HBr media. These methods were successfully applied to the analysis of platinum in real samples. © 2001 Society of Chemical Industry     

Concurrency control in hierarchical multidatabase systems

Over the past decade, significant research has been done towards developing transaction management algorithms for multidatabase systems. Most of this work assumes a monolithic architecture of the multidatabase system with a single software module that follows a single transaction management algorithm to ensure the consistency of data stored in the local databases. This monolithic architecture is not appropriate in a multidatabase environment where the system spans multiple different organizations that are distributed over various geographically distant locations. In this paper, we propose an alternative multidatabase transaction management architecture, where the system is hierarchical in nature. Hierarchical architecture has consequences on the design of transaction management algorithms. An implication of the architecture is that the transaction management algorithms followed by a multidatabase system must be composable– that is, it must be possible to incorporate individual multidatabase systems as elements in a larger multidatabase system. We present a hierarchical architecture for a multidatabase environment and develop techniques for concurrency control in such systems. Edited by R. Sacks-Davis. Received June 27, 1994 / Accepted September 26, 1995     

Environmental Overview of the Sardar Sarovar Project

An overview of the various studies conducted to assess the environmental, ecological and social impacts, both positive and negative, of the Sardar Sarovar Project is presented. These studies have generally attempted to enhance the positive impacts, and to reduce the negative ones. The Sardar Sarovar Project is by far the most studied water project in the developing world, especially in social and environmental terms. The river Narmada and its numerous tributaries are a part of a very diverse system. The environmental impact assessment (EIA) of the river valley development is a complex task. The intricate interactions between various parameters, many of which cannot be definitively predicted, make EIA studies extremely difficult. The success of this project depends on how fast and how efficiently the various governmental agencies can work together with the NGOs, academics, the general public, and of course the politicians and policy makers.     

Effect of inert fillers on diffusion and controlled release of penetrant in polymer matrices

This study investigates the characteristics of leaching into a solvent of an active used as termiticide, Bifenthrin® (a synthetic pyrethroid) entrapped in polymer, and the effect of layered silicates on this diffusion. Two contrasting solvents, water and acetone, were used to understand this phenomenon; the active is soluble in acetone but has very low solubility in water. The data are used to understand the migration characteristics of Bifenthrin when encapsulated in polyurethane to form a termite barrier. The absorption characteristics of Bifenthrin in polyethylene were also studied for comparison. Bifenthrin-polyurethaneblends containing 0, 0.5, and 5% of layered silicates were prepared and monitored for the release of Bifenthrin. Using the time-concentration dependence of the active in polymer, diffusion coefficients of Bifenthrin from the polymer were inferred assuming Fickian diffusion. The presence of silicates had no significant effect on the diffusion behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Predicting excavation methods and rock support: a case study from the Himalayan region of India

The Tapovan Vishnugad hydropower project (4 × 130 MW) in the Himalayan region of India, has been used as a case study to compare the problems and cost-effectiveness of a TBM or drill and blast excavation of the headrace tunnel and to assess the rock support measures for the powerhouse cavern. The NTH time and cost prognosis model indicated that the TBM would give a better weekly advance rate and unit excavation cost for the headrace tunnel. The Phase 2 finite element numerical modeling tool and the Hoek–Brown failure criterion were used to analyse the stresses and displacements likely to be experienced in the underground excavations. The rock support determined was compared with that indicated using the Q-method. The work has shown that numerical modeling can prove very useful in supplementing the results, provided the input parameters are accurate and take into account both direct measurements and judgment based on experience of the actual ground conditions.     

Global optimization of mixed-integer nonlinear (polynomial) programming problems: the Bernstein polynomial approach

In this paper, we propose an algorithm for constrained global optimization of mixed-integer nonlinear programming (MINLP) problems. The proposed algorithm uses the Bernstein polynomial form in a branch-and-bound framework. Ingredients such as continuous relaxation, branching for integer decision variables, and fathoming for each subproblem in the branch-and-bound tree are used. The performance of the proposed algorithm is tested and compared with several state-of-the-art MINLP solvers, on two sets of test problems. The results of the tests show the superiority of the proposed algorithm over the state-of-the-art solvers in terms of the chosen performance metrics.     

Precise spring constant assignment in elastic network model for identification of vibration frequency and modeshape

We presented a feasible framework of studying dynamics of macromolecules by applying elastic network model (ENM) and vibration spectroscopy. We first identified the precise force constants of covalent bonds commonly observed in macromolecules by matching their reported Raman shifts data with predicted wavenumbers determined by normal mode analysis (NMA). Assigning the obtained spring constants to other small chemical compounds such as ethynyl isocyanide (C3HN) and diacetylene (C4H2), we not only predicted their vibration wavenumbers precisely but also identified their individual mode shapes from NMA. We extensively tested this chemical information based ENM with one of amino acids, cysteine. Subsequent comparison of frequencies and modeshapes also yields a strong agreement between computed and experimental data. Consequently, the proposed method enables us to identify low frequency modeshapes that are in general functionally important collective motions of macromolecules but have hardly been revealed experimentally even using terahertz spectroscopy.     

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