Doctor of Philosophy

dissertationThe bituminous sand deposits of Utah are estimated to contain 25 - 29 billion barrels of oil in place and are the largest petroleum resource of this type in the United States. There are six major deposits of commercial importance* some of them potentially amenable to surface mining techniques. In this investigation an experimental program was conducted to determine the feasibility of an aboveground fluidized bed thermal process rfor the recovery of - a synthetic crude from the minable bituminous sand deposits of Utah. A continuous bench-scale, fluidized bed reactor, designed for a maximum throughput capacity of 2.25 kilograms of feed sand per hour, was developed for this investigation. Bituminous sands of distinctly different origin were processed, that is, (i) the Sunnyside bituminous sand, a deposit of fresh water origin having a bitumen content of 8.5 percent by weight, and (ii) the Tarsand Triangle sand, a deposit of marine origin having a bitumen content of 4.5 percent by weight. The effects of the following variables on the synthetic liquid yield and on the liquid quality were studied: Reactor Temperature: 698 - 898 K Solids Retention Time: 20.4 - 31.4 minutes Particle Size of Feed Sand: 162 - 507.5 microns The maximum liquid yield for the Sunnyside sand, 70 weight percent of the bitumen fed, was obtained at 773 K and a solids retention time of 20.4 minutes for a feed sand particle size of 358.5 microns. The remaining 30 weight percent of the bitumen was converted to coke and light hydrocarbon gases. Increasing the solids retention time lowered the liquid yield and shifted the-temperature for maximum liquid yield to a lower value. The physical properties and chemical nature of the synthetic liquid obtained were correlated with the reactor temperature. The synthetic liquid obtained was paraffinic and contained a low percentage of heteroatoms. A mechanism for the thermal cracking of the bitumen has been developed to explain the results obtained. Extrapolation of the data to a solids retention time of 16 minutes predicts a yield of 80 weight percent synthetic liquid, 8 weight percent light hydrocarbon gases (C-j - C4 ), and 12 weight percent coke. The thermal processing of Tarsand Triangle sand was studied as a function reactor temperature in the range 723 - 898 K. It was found that the liquid yield was lower than that obtained with the Sunnyside feed. The maximum liquid yield of 51 weight percent based on bitumen fed was obtained at 798 K and a retention time of 27.2 minutes. Despite the differences in the origin of the feed sand and the operating temperature range, the yield of coke (19 - 22 wt %) was comparable to Sunnyside coke yields. The liquid product was more aromatic than the Sunnyside liquid product

Recent Developments in Anti-Tank Ammunition

Every advance in anti-tank ammunition has been matched by advances in armour material or vice-versa. This applies both to kinetic energy and chemicai energy type of ammunition. Today the kinetic energy ammunition appears to have an upper hand over armour. In t his paper, a brief survey of the modern FSAPDS ammunition, its design aspects and its material technology is made.The capabilities of HEAT type of ammunition are also discussed and the likely trends in ammunition technology are indicated. Some futuristic developments in the field of propulsion are briefly mentioned

Numerical and experimental investigation of FBG strain response at cryogenic temperatures

Strain response of FBG sensors are investigated at various temperatures from 298 K to 4.2 K. Numerical modelling is carried out for acrylate coated, substrate-free fiber Bragg grating (FBG) sensors at room temperature of 298 K and cryogenic temperatures of 77 K, 10 K and 4.2 K. A 1550 nm Bragg wavelength (λB) FBG sensor is modelled and simulated for applied strain (ε) ranging from 0 to 800 µm/m. The Bragg wavelength shifts (ΔλB) thus obtained are compared with the experimentally investigated values obtained by subjecting the FBG sensor to axial strain, with its sensing part not being bonded to any surface. The MTS25 tensile machine with a cryostat under vacuum conditions (10-4 mbar pressure) is used for the experiments and the required temperatures are maintained using liquid Nitrogen (LN2) and compressed Helium gas (He). The Bragg wavelength shift (ΔλB) versus induced strain (ε) is regressed with a linear polynomial function and the strain sensitivity obtained in both the cases are discussed

Professor DS Kothari : The Architect of Defence Science in India

Defence science in India owes its origin and early growth to Professor DS Kothari. From humble beginnings the Defence Research and Development Organization (DRDO) has grown into a major national scientific agency over the last four and a half decades