Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
The aim of this work was to check the possibility of using a concrete matrix to immobilize\ncontaminants from ash (fly and bottom) originating from the combustion of solid municipal waste.\nThis work presents tests of ash from a Polish incineration plant. Nowadays, the management of\nash poses a big problem with respect to the high concentration of contaminants that constitutes\nan environmental nuisance (heavy metals, chlorides, sulfates, etc.). The excessive leaching of\ncontaminants disqualifies ash from being deposited in landfills for hazardous wastes. Bottom ash\nfollowing the combustion of solid municipal waste mainly contains calcium (23.81%), chlorine (5.44%)\nand heavy metal .............................
In order to study the effect of carbon nanotubes (CNTs) on the flame retardancy of carbon \nfiber (CF)/epoxy resin (EP) composites, CF/EP and CNTs/CF/EP composites were prepared by \nsolution blending. The flame retardancy and thermal stability were studied by cone calorimetry and \nthermogravimetric analysis. It was found that CNTs and CF had a certain synergistic effect on \nimproving flame retardancy and thermal stability of EP. The peak heat release rate of F7N7, which \nrepresents the EP composites with 0.7 wt % CF and 0.7 wt % CNTs, was minimal. The total smoke \nproduction of F5N5 which represents the EP composites with 0.5 wt % CF and 0.5 wt % CNTs was \nthe smallest, which was decreased by 43.04% more than the EP. The initial decomposition \ntemperature of F7N7 was about 14 degreeC higher than that of F7, and the mass loss at Tmax was greatly \nreduced. The apparent activation energy of F7N7 is 2.7 kJ.mol^-1 more than EP. Finally, the tensile \nand flexural strength of the composites were also improved, so it could be applied to a high\nperformance matrix of CF/EP composites, which are usually used as the advanced composites in\nthe aerospace field....
In this work, a novel route is discussed to produce in one step ZnO/Burkeite powders by the\nmodified solution combustion method. The ZnO particles enhance the photocatalytic activity in the\ndegradation of Rhodamine B, in which Burkeite mineral acts as a support due to the pH-dependent\nmorphology of the particle aggregates of the as-synthesized powders. The X-ray diffraction (XRD)\ncharacterization shows the presence of a heterostructure: ZnO/Burkeite. The Scanning Electron\nMicroscopy (SEM) image shows a morphological dependence with the pH of the solution used for\nthe synthesis. The results show that the system with the highest degradation (92.4%) corresponds to\nthe case in which ZnO/Burkeite heterostructure was synthesized with a pH 11....
The combustion process in hydrocarbon fuels, involves complicated chemical\nreactions associated with bond braking, radicals production and heat generation\nwhich are responsible for flames initiation. The conditions, such as pressure,\ntemperature and mixture strength, make a strong influence on combustion.\nThis paper reports an investigation of combustion characteristics of premixed\npropane/air flames and the effects of initial conditions on heat production\nrates, emissions (combustion products) and final equilibrium pressure\nand temperature values......................
The present work addresses the influence of the support on the catalytic behavior of\nCo3O4-based catalysts in the combustion of lean methane present in the exhaust gases from natural\ngas vehicular engines. Three different supports were selected, namely Gamma-alumina, magnesia and\nceria and the corresponding catalysts were loaded with a nominal cobalt content of 30 wt. %.\nThe samples were characterized by N2 physisorption, wavelength dispersive X-ray fluorescence\n(WDXRF), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and\ntemperature-programmed reduction with hydrogen and methane. The performance was negatively\ninfluenced by a strong cobalt-support interaction, which in turn reduced the amount of active cobalt\nspecies as Co3O4. Hence, when alumina or magnesia supports were employed, the formation of\nCoAl2O4 or Co-Mg mixed oxides, respectively, with a low reducibility was evident, while ceria\nshowed a lower affinity for deposited cobalt and this remained essentially as Co3O4. Furthermore,\nthe observed partial insertion of Ce into the Co3O4 lattice played a beneficial role in promoting\nthe oxygen mobility at low temperatures and consequently the catalytic activity. This catalyst also\nexhibited a good thermal stability while the presence of water vapor in the feedstream induced a\npartial inhibition, which was found to be completely reversible....
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