Cenosphere

About: Cenosphere is a research topic. Over the lifetime, 894 publications have been published within this topic receiving 14712 citations. The topic is also known as: cenospheres.

Compression properties of syntactic foams: effect of cenosphere radius ratio and specimen aspect ratio

Abstract: The present work is aimed at characterizing syntactic foams for flatwise (specimen aspect ratio of 0.5) properties and investigating the effect of change in the internal radius of cenospheres. The density and mechanical properties of the syntactic foam can be changed while keeping cenosphere volume fraction and particle–matrix interfacial area the same by using cenospheres of same outer radius but different inner radius. Five types of cenospheres, with the same mean outer radius but a different internal radius, have been selected for the fabrication of syntactic foams. ASTM C 365-94, a standard for the flatwise compressive properties of sandwich cores, is followed in the present work. The results obtained in the study are compared with the results of edgewise (specimen aspect ratio of 2) compressive properties evaluated in earlier work. Results show an increase in compressive strength and modulus with decrease in internal radius of cenospheres. The peak compressive strength and modulus were measured to be higher for the specimens tested in flatwise orientation compared to that in edgewise orientation. Varying only one parameter, the internal radius of cenospheres, helped in understanding the role of cenospheres and matrix resin in deformation and fracture process of syntactic foams.

Compressive characteristics of A356/fly ash cenosphere composites synthesized by pressure infiltration technique

Abstract: Loose beds of hollow fly ash particles (cenospheres) were pressure infiltrated with A356 alloy melt to fabricate metal-matrix syntactic foam, using applied pressure up to 275 kPa. The volume fractions of cenospheres in the composites were in the range of 20–65%. The processing variables included melt temperature, gas pressure and particles size of fly ash. The effect of these processing variables on the microstructure and compressive properties of the synthesized composites is characterized. Compressive tests performed on these metal-matrix composites containing different volume fractions of hollow fly ash particles showed that their yield stress, Young's modulus, and plateau stress increase with an increase in the density. Variations in the compressive properties of the composites in the present study were compared with other foam materials.

Fly ash collected from electrostatic precipitators: microcrystalline structures and the mystery of the spheres.

Abstract: Scanning electron micrographs demonstrate the presence of microcrystalline structures on the surface of coal-derived fly ash samples taken from electrostatic precipitator hoppers. Cenospheres (hollow spheres) were found to be packed with smaller cenospheres, which were also packed with spheres. Microspheres, apparently formed by uneven heating, are encapsulated in the parent sphere. Chemical analyses provide a basis for the postulation of a mechanism of formation for plerospheres (hollow spheres packed with spheres) and microcrystals.

Mechanical and thermal characteristics of high density polyethylene-fly ash Cenospheres composites

Abstract: Fly ash Cenospheres was used as reinforcing filler in High density polyethylene (HDPE) to develop lightweight composites. Cenospheres are inert hollow silicate spheres. Cenospheres are a naturally occurring by-product of the burning process at coal-fired power plants, and they have most of the same properties as manufactured hollow-sphere products. Cenospheres are primarily used to reduce the weight of plastics, rubbers, resins, cements, etc. used extensively as filler lubricants in oil drilling operations under high heat and high stress conditions down the hole. Also used as oil well cementing, mud putty and similar applications. Cenospheres were first used in the United States as an extender for plastic compounds, as they are compatible with plastisols thermoplastics, Latex, Polyesters, Epoxies, Phenolic resins and urethanes. The compatibility of Cenospheres with special cements and adhesives coating and composites have been well identified. Cenospheres are widely used in a variety of products, including sports equipments, insulation, automobile bodies, marine craft bodies, paints, and fire and heat protection devices. Typically applied in gypsum board jointing compounds, veneering plasters, stuccos, sealants, coating and cast resins. Providing the advantages of reduces weight, increased filler loadings, better flow characteristics, less shrinkage and warping and reduces water absorption. In order to improve the interaction between the inorganic filler and the organic matrix, the Cenospheres were surface treated with silane coupling agent and HDPE-g-dibutyl maleate was used as compatibilizer. The tensile and thermal properties of the composites were measured according to ASTM methods. The results reveal that, both surface modification of Cenospheres accompanied by compatibilization led to the substantial improvement to mechanical properties and thermal stability of the composites.

The Physical Transformation of the Mineral Matter in Pulverized Coal Under Simulated Combustion Conditions

Abstract: The physical transformation of the mineral matter in coal has been studied in a laboratory furnace using size-graded, pulverized samples of a lignite and a bituminous coal. The mineral matter is originally distributed in micron-size inclusions in the coal particles. The paper illustrates how the final particle size distribution of the ash produced at combustion temperatures of 1250 to 1830K is determined by a combination of agglomeration of fused mineral matter, cenosphere formation due to gas evolution and vaporization and recondensation of volatile constituents