No description available.

No description available.

No description available.

No description available.

No description available.

There is an economic incentive to substitute energy and capital-intensive conventional gas separation schemes based on cryogenic distillation. Absorption has potential advantages over low-temperature schemes as it does not rely on high refrigeration requirements to perform the separation. An optimisation-based synthesis framework has been developed that integrates distillation and absorption-desorption schemes. This methodology is able to quantitatively resolve the numerous tradeoffs between the various capital and operating factors and systematically suggest new design configurations. A multilevel modelling approach enables the accommodation of absorption-desorption separation options in the distillation orientated framework supported by COLOM® (©Centre for Process Integration, University of Manchester). Improved shortcut models for reboiled absorption and distillation columns have been proposed, which are suitable for exploitation in the developed synthesis framework. A new methodology for heat integration is proposed that achieves efficient heat recovery and proposes a configuration of the heat exchanger network. This methodology works in harmony with the optimisation framework. Simultaneous optimisation of the separation system, the heat exchanger network and the refrigeration system offers the opportunity of achieving a superior overall configuration. The structural and operating variables of the separation system are optimised by Simulated Annealing. As a stochastic optimisation method, SA can deal with the large scale of the problem and its discontinuous and non-linear nature imposed by the feasibility limits of the separations and the model equations. The optimal separation configurations are selected on the grounds of minimum capital and operating costs. An analysis of costing methods is provided which aims at rationalising the basis for cost estimation. The application of the developed synthesis methodology is illustrated by a number of examples of relevance to the natural gas processing and refinery gas processing. Results will emphasise the functionality of the methodology as a tool for quantitative evaluation of preliminary designs and realisation of highly integrated and efficient process concepts.

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Call number: LD2668 .T4 1950 D36 / Master of Science

Thesis Submitted to the Faculty of Medicine University of the Witwatersraiu', Johannesburg for the Degree of Doctor of Philosophy (Medicine) Johannesburg 1976 / An attempt was made to fortify sugar with iron in order to prevent the development of iron deficiency. It was possible to add various iron salts and ascorbic acid to sugar without discolouring the vehicle even after storage for many months under hot humid conditions. The absorption of iron from fortified sugar and cereal meals was then measured in human volunteers using either an "extrinsic tag" to label the iron compound or intrinsically labelled food iron. / IT2018

A thesis submitted to the Faculty of Medicine University of the Witwatersrand, Johannesburg for the Degree of Doctor of Philosophy. / The investigations which make up the body of this thesis touch on various aspects of iron absorption. Although many of the factors governing iron absorption have been elucidated specific problems remain to be defined in greater detail. The aim of these investigations was therefore to define more fully some of the quantitative and qualitative aspects of dietary iron absorption / IT2018