Flexible (non-bonded) polymeric sewer linings are used extensively to renovate both gravity and pressure pipes. Linings for both types of pipe are subject to collapse pressures, and in the case of gravity pipes this is the dominant source of loading; the efficient design of linings to sustain collapse pressures is therefore an important problem. In this paper, the buckling of an ideal thinwalled elastic lining in a rigid cylindrical cavity is first presented as a simple closed form solution, and The effect of a representative small imperfection shown to be significant. The different types of imperfection that can be encountered in practical lined pipe systems are identified, and the situations in which each can arise are discussed. A generalised procedure for obtaining the structural imperfections in, and hence buckling capacities of, practical systems is then presented and two example applications are used to illustrate its application in specific situations.

A two-dimensional constant heating rate thermoelastic model has been used to develop design and selection criteria for refractory components of linings of high-temperature furnaces and process vessels. The criteria are in the form of resistance to fracture initiation and resistance to damage parameters which account for the influence of thermal and mechanical properties, geometry, and temperature range, while distinguishing between the heating and cooling cases. The resistance to fracture initiation parameter ɸs is the maximum rate at which a shape can be heated or cooled through a specified temperature range without causing fracture. The damage resistance parameter Rd is expressed as the ratio of surface energy per unit area to the elastic strain energy available for crack propagation. Both parameters can be quickly estimated for arbitrary conditions with the aid of tabulated solutions for the maximum principal tensile stress and total strain energy Thermoelastic analyses were used to interpret published results of a variety of thermal shock experiments. Thermal conditions associated with water quenching, radiative furnace heating, gas burners, and controlled heating were simulated using appropriate analytical solutions. Finite element analysis was used to compute maximum principal tensile stresses and elastic strain energy. A simple procedure was developed to invert the stress solution and thereby determine the instant of fracture. Good agreement between thermoelastic predictions and published experimental results with regard to strength retained versus thermal shock relationships, location of fracture, and safe heating rates provided justification for a thermoelastic approach to the thermal shock. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Low cement castable (LCC) refractory linings, over recent years, have superseded refractory bricks in many high temperature applications. There are concerns however, pertaining to their dry-out. In particular the catastrophic destruction of LCC shapes or linings as a result of phenomenate rmede xplosives palling. This thesis describes the study of both the on-site treatments of LCCs and the physicochemical changes that occur during heating. Two types of explosive spalling event are classified,b asedo n on-siteo bservationsa ndp ost-mortems tudy. A model is presented that describes the physicochemical changes in a LCC system as it is heated from ambient to 450°C. From this model a zone of high vulnerability to explosion has been identified between 230-280°C. The dehydration of the hydrated alumina phase gibbsite (AH3), within this zone, is identified as a possible cause of explosive spalling. An investigation of polypropylene fibres, which are added to LCCs as anti-explosion additives, found that the fibres block porosity between1 60-240°CI.t is suggested that this additive system is not optimised and that polymer fibre blends may be more advantageous. The diffusion characteristics of a LCC system cured at 5 and 20°C is presented. It was found that at the lower curing temperature the diffusion rate was lower. This supports the recommendation for the use of high curing temperature to facilitate the drying of LCCs and reduce the risk of explosive spalling. A list of guidelines that could be used to establish benchmark standards for the development of best practice in industry has been compiled from the results of these studies.

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This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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M.Ing. / In this study it is shown that numerical analysis, and more specifically computational fluid dynamics can be used to investigate, compare, predict and design lining/cooling system combinations for blast furnaces’ in order to ensure longer campaign life and better performance. Three currently available cooling systems namely, copper staves are investigated. These combined with four different refractory materials, namely high alumina, silicon carbide, semi-graphite and graphite, stated in order of increasing thermal conductivity.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

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