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.

Separation science is a multi‐faceted discipline, underpinning almost all other fields of science and technology. Its scope encompasses fundamental and cutting edge processes and technologies, based upon exploitation of the physical distribution of chemical and biochemical species between solid, liquid or gaseous ‘phases’, facilitating their separation, purification, and analysis. Separation science plays a particularly pivotal element within the majority of modern analytical methods, methods which continue to support all manner of cutting edge scientific endeavour, including, for example, the current ‘‐Omics’ scientific revolution. As inferred above, separation science can of course vary considerably in physical form and scale, from micro‐extraction, to bench‐top chromatographic methods, to large scale industrial process isolation and preparative systems. However, in each and every case there exists several common factors governing success, perhaps the most significant of which is so‐called ‘phase selectivity’, or the fundamental chemical and biochemical interaction between a molecularly defined/controlled surface or phase, and the individual target or group of molecules.

We investigate experimentally the effects of acoustic forces on submicron aerosol in a channel flow. This technique can potentially overcome some of the limitations of conventional separation systems and provide advanced manipulation capabilities such as sorting according to size or density. The theoretical framework for acoustophoresis at such small length scales where molecular effects are expected to be significant is still incomplete and in need of experimental validation. The main objectives of this thesis are to identify the physical limitations and capabilities of acoustophoretic manipulation for submicron aerosol particles. Two sets of experiments were carried out: first, qualitative results revealed that acoustic manipulation is possible for submicron particles in air and that the acoustic force follows the trend expected by theoretical models developed for particles in inviscid fluids. The acoustic force on submicron particles was estimated in a second set of measurements performed with quantitative diagnostic tools. Comparison of these results with available theoretical models for the acoustic radiation forces demonstrates that for such small particles additional forces have to be considered. At submicron length scales, the magnitude of the forces observed is orders of magnitude higher than the predictions from the inviscid theory. One potential application for acoustophoresis is specifically investigated in this thesis: assist electrostatic precipitation (ESP) samplers to target very small aerosols, such as those carrying airborne viruses. To identify the shortcomings of ESP samplers that acoustophoresis should overcome, two ESP designs have been investigated to quantify capture efficiency as a function of the particle size and of the air velocity in a wind tunnel. The results reveal that both designs have limitations when it comes to sampling submicron aerosol particles. When exposed to polydispersed suspensions they behave as low-pass filters. / <p>QC 20161125</p>

Thesis advisor: Edward J. Kane / Portfolio theory attempts to answer two fundamental questions concerning financial investments. In the language of the old adage "Don't put all of your eggs in one basket," the two questions arising are: 1) "How many baskets should the eggs be put into?" and 2) "How many eggs should be put into each basket?" / Thesis (PhD) — Boston College, 1972. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

Thesis presented for the degree of Magister Technologiae: Chemistry in the Faculty of Applied Sciences at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY / The separation of isomers with similar chemical structures is one of the most difficult procedures in chemistry. This is because their physical and chemical properties are generally so similar that most of the common techniques are not successful. In such situations one employs host-guest chemistry, as a tool of separation technology. In this thesis three aromatic hydrocarbon host compounds 9,9’-bianthryl (H1), 9,9’-spirobifluorene (H2) and trans-2,3-dibenzoylspiro(cyclopropane-1,9’-fluorene) (H3) were investigated in terms of their selectivity towards heterocyclic aromatic compounds (pyridine, PYR; piperidine, PIP; morpholine, MOR and 1,4-dioxane, DIO), cyclohexanone derivative compounds (cyclohexanone, CYHA; 2-methylcyclohexanone, 2-MCYHA; 3-methylcyclohexanone, 3-MCYHA and 4-methylcyclohexanone, 4-MCYHA) and the xylene isomers (ortho-xylene, ox; meta-xylene, mx and para-xylene, px). The H1, H2 and H3 host compounds were combined with a series of the heterocyclic compounds and six inclusion compounds were formed: H1•MOR, H2•2PYR, H2•PIP, H2•MOR, H2•DIO and H3•PYR. In the second part the derivatives of cyclohexanone formed inclusion compounds with the hosts H1 and H2. The H1•2CYHA, H1•ANT, H1•0.5(2-MCYHA) and H3•CYHA structures were obtained. In the third part the H1 formed clathrates with ox and px; H2 and H3 only formed clathrates with px and ox respectively. The following four structures were obtained: H1•0.5ox, H1•0.5px, H2•0.5px and H3•ox and were analysed by single crystal X-ray diffraction (SCXD), powder X-ray diffraction (PXRD), proton nuclear magnetic resonance spectroscopy (1H-NMR), thermal gravimetry (TG) and differential scanning calorimetry (DSC). It wasconcluded that H2 discriminates between the four heterocyclic compounds as follows: PIP > MOR ≈ DIO ≈ PYR and this can be explained by the 1H-NMR results and the packing features. In analysis of the xylene isomers, it was found that the three hydrocarbon host compounds H1, H2 and H3 efficiently discriminate between the isomers by forming inclusion compounds. H1 enclathrates both ox and px but prefers the former. This can be explained in terms of the packing features and lattice energies. H2 and H3 only enclathrate px and ox respectively. It was concluded that host compounds with small conformational movements are potentially good in selective inclusion.

Lee Ka-lun. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references. / Acknowledgments --- p.ii / Abstract --- p.iii / Table of Contents --- p.v / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Phase Separation in Glass-Forming Alloys --- p.2 / Chapter 1.1.1 --- Metallic Glass --- p.2 / Chapter 1.1.2 --- Phase Separation in Metallic Glasses --- p.3 / Chapter 1.1.3 --- Phase Separation in the Undercooled Melts of Glass-Forming Alloys --- p.4 / Chapter 1.2 --- Theory of Phase Separation --- p.5 / Chapter 1.2.1 --- Thermodynamics of Phase Separation --- p.5 / Chapter 1.2.2 --- Phase Separation by Nucleation and Growth --- p.7 / Chapter 1.2.3 --- Cahn's Theory of Spinodal Decomposition --- p.8 / Chapter 1.3 --- Experimental Method to Achieve High Undercooling --- p.11 / References --- p.14 / Figures --- p.15 / Chapter Chapter 2: --- Phase Separation in Undercooled Molten Pd80Si20 --- p.23 / Abstract --- p.24 / Introduction --- p.25 / Experimental --- p.29 / Results --- p.30 / Discussions --- p.36 / References --- p.45 / Figures --- p.47 / Chapter Chapter 3: --- Metastable Liquid Phase Separation in Undercooled Molten Pd40.5Ni40.5P19 --- p.60 / Abstract --- p.61 / Introduction --- p.62 / Experimental --- p.62 / Results and Discussions --- p.63 / References --- p.68 / Figures --- p.69 / Chapter Chapter 4: --- Crystallization of Spinodal Decomposed Melts of Pd80Si20 --- p.74 / Introduction --- p.75 / Experimental --- p.76 / Results --- p.77 / Discussions --- p.80 / References --- p.84 / Figures --- p.85

No description available.

Graduation date: 1995

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

In warm and humid climates, a primary source of building energy consumption is dehumidification of conditioned air supplied to the building spaces. The proposed system utilizes a selective membrane to remove water vapor from ambient air as opposed to a vapor compression cycle or a desiccant. This work provides an analysis of the membrane dehumidification system with a focus on the energy performance of the system. A system performance goal was set at the beginning for a given inlet and outlet ambient air condition and a total cooling load of one ton. The target COP of the combined sensible and latent cooling is 3.58 with a target value for only the latent system of 3.34. Two different simulations were developed including an initial simulation which uses a basic mass transfer model and a simpler condenser model. The initial model was used to develop the system, analyze operating parameters and provide initial performance results. The initial simulations indicate that the system requires two optimizations to meet the target performance: condenser pressure optimization and the use of multiple membrane segments operating at different pressures. The latent only COP including the optimizations was a maximum of 4.23. A second model was then developed which uses a more detailed mass transfer model and a more detailed condenser model based on the operating conditions. This simulation yielded a maximum latent only COP of 4.37 including the optimizations. The work also analyzes two different combined systems capable of providing both sensible and latent cooling. The first utilizes a conventional vapor compression cycle for sensible cooling and has a maximum COP of 3.93. The second uses multiple evaporative coolers in between multiple membrane dehumidification steps and was found to have a maximum COP of 3.73. Second law analysis of the systems was also conducted and found that the greatest reduction in latent system exergy loss can be obtained by improving the selectivity of the membrane. Apart from improving the membrane selectivity, the results show the greatest improvement can be found in improving the operation of the gas compression devices.