Generalized Gravi-Electromagnetism

A self consistant and manifestly covariant theory for the dynamics of four charges (masses) (namely electric, magnetic, gravitational, Heavisidian) has been developed in simple, compact and consistent manner. Starting with an invariant Lagrangian density and its quaternionic representation, we have obtained the consistent field equation for the dynamics of four charges. It has been shown that the present reformulation reproduces the dynamics of individual charges (masses) in the absence of other charge (masses) as well as the generalized theory of dyons (gravito - dyons) in the absence gravito - dyons (dyons). key words: dyons, gravito - dyons, quaternion PACS NO: 14.80H

Characterization and catalytic activity of Ni-W/SiO₂-Al₂O₃ hydrocracking catalysts

169-175Characterization of Ni-W SiO2-Al2O3 catalysts was carried out by microcalorimetry, TPR and oxygen chemisorption. The effect of incorporation of individual metals and their sequence of addition to the support on the properties and catalytic activity for cyclohexene hydrogenation and cumene cracking was investigated. While the addition of nickel to SiO2-Al2O3 has little effect on the acidity, tungsten has generated some new strong acid sites, which do not seem to have beneficial effect for cumene cracking. Low temperature TPR peak in the bimetallic catalysts falls around 760 K due to Ni-W species while the high temperature peak around 1115-1223K corresponds to W species. W/SiO2-Al2O3 has a lower oxygen chemisorptions than its nickel counterpart but has a higher hydrogenation rate. Tungsten is the active metal for hydrogenation. W-Ni/SiO2-Al2O3 catalyst has better hydrogenation and cracking activity

Characterization and catalytic activity of Ni-W/Si02-Al203 hydrocracking catalysts

Characterization of Ni-W SiOrAI203 catalysts was carried out by microcalorimetry, TPR and oxygen chemisorption. The effect of incorporation of individual metals and their sequence of addition to the support on the properties and catalytic activity for cyclohexene hydrogenation and cumene cracking was investigated. While the addition of nickel to Si02-AI203 has little effect on the acidity, tungsten has generated some new strong acid sites, which do not seem to have beneficial effect for cumene cracking. Low temperature TPR peak in the bimetallic catalysts falls around 760 K due to Ni-W species while the high temperature peak around 1115-1223K corresponds to W species. W/SiOrAI203 has a lower oxygen chemisorption than its nickel counteqJart but has a higher hydrogenation rate. Tungsten is the active metal for hydrogenation. W-Ni/SiO2-Al203 catalyst has better hydrogenation and cracking activity

Control of mesoporosity in alumina

157-161The textural properties of the alumina carrier play a major role in governing the performance of alumina based heterogeneous catalysts. The regulation of the pore size distribution in the support is of paramount importance in the development of a promising catalyst. The role of peptising agent, combustible additives and binder in regulating the mesoporosity has been investigated using high pressure mercury porosimetry. Control of pore size in 18-50Å radii range can be achieved by peptising alumina monohydrate (boehmite) by 1.5% nitric acid. Additives like polyvinyl alcohol and polyethylene glycol have broadened the mesopores while carbon black has drastically increased pores in 50-100Å range. Addition of 10% calcined alumina as binder has been found suitable to maintain pores <50 Å radii