Dissertations / Theses: 'Crystallisation'

1

Francis, Philip Sydney, and phil francis@rmit edu au. "Crystallisation spectrometer." RMIT University. SET, 2002. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20050617.121435.

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An improved crystallisation spectrometer has been designed, built and tested. It is to be used by others to gain new knowledge about the solidification of matter by study of the crystallisation of hard sphere colloid samples that are an established model for the behaviour of some aspects of atoms. In this crystallisation spectrometer, expanded and collimated green laser light is Bragg scattered from the colloidal crystals as they form, and the diffracted light is focused by a liquid filled hollow glass hemispherical lens onto low cost CCD array detectors that are rotated about the optical axis to average the intensities around the whole Debye-Scherrer cone of scattered light. The temperature of the sample is controlled to +/-0.1a, and because of the ability to change the refractive index of the sample particles with temperature, this is utilised to control the amount of scattering from the sample Also, this spectrometer uniquely exploits the refractive index match of the colloidal particles, the solvent, the bath liquid, and the glass used for both the sample bottle and the hollow glass hemisphere. A unique facility has been incorporated to permit tumbling of the sample prior to the measurement commencing to shear-melt any pre-existing crystals. This ensures that the sample is completely fluid and is at the correct temperature at the start of the measurement. The instrument is assembled on an optical table and is computer controlled. Results presented show that this new spectrometer with its use of the whole Debye-Scherrer cone of Bragg scattered light and other enhancements gives insight into the crystallisation process more than one order of magnitude of time earlier than previous light scattering experiments, providing new knowledge about the crystallisation process.

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2

Aumann, Simon. "Nearcritical percolation and crystallisation." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-177436.

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This thesis contains results on singularity of nearcritical percolation scaling limits, on a rigidity estimate and on spontaneous rotational symmetry breaking. First it is shown that - on the triangular lattice - the laws of scaling limits of nearcritical percolation exploration paths with different parameters are singular with respect to each other. This generalises a result of Nolin and Werner, using a similar technique. As a corollary, the singularity can even be detected from an infinitesimal initial segment. Moreover, nearcritical scaling limits of exploration paths are mutually singular under scaling maps. Second full scaling limits of planar nearcritical percolation are investigated in the Quad-Crossing-Topology introduced by Schramm and Smirnov. It is shown that two nearcritical scaling limits with different parameters are singular with respect to each other. This result holds for percolation models on rather general lattices, including bond percolation on the square lattice and site percolation on the triangular lattice. Third a rigidity estimate for 1-forms with non-vanishing exterior derivative is proven. It generalises a theorem on geometric rigidity of Friesecke, James and Müller. Finally this estimate is used to prove a kind of spontaneous breaking of rotational symmetry for some models of crystals, which allow almost all kinds of defects, including unbounded defects as well as edge, screw and mixed dislocations, i.e. defects with Burgers vectors.

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3

Ravenhill, Emma Rosanna. "Crystallisation at functionalised interfaces." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/101542/.

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Within this thesis, a broad range of microscopic and spectroscopic methods are employed to investigate crystallisation processes initiated at novel functionalised interfaces. This approach combines in situ optical microscopy (OM) with several surface sensitive techniques, including atomic force microscopy (AFM), scanning electron microscopy (SEM) and interferometry, with further structural analysis provided via Raman spectroscopy and X-ray diffraction (XRD). This method allows the key mechanistic phenomena to be elucidated to a high level of detail for crystal growth processes with extreme industrial and biological importance. The main focus of the thesis is around a specific industrial problem, concerning the detrimental growth of inorganic crystalline materials within internal combustion engines. Firstly, the deposit structure is revealed by implementing analytical techniques such as SEM, Raman spectroscopy and XRD to characterise real engine deposits. This in depth analysis demonstrates the high abundance of the calcium sulfate polymorphs bassanite (CaSO4⋅0.5H2O) and anhydrite (CaSO4) within the deposit, providing initial insights into this unfavourable growth process. These deposit growth mechanisms are further studied via in situ OM, monitoring calcium sulfate crystallisation at aqueous-organic liquid-liquid interfaces to mimic real life conditions within the engine environment. As well as providing a wealth of knowledge on the deposit formation process, this approach highlights the unique properties liquid-liquid interfaces offer for crystal growth, revealing via Raman spectroscopy and XRD analysis their applicability for synthesising typically unstable materials under low energy, ambient conditions. This industrial problem is further investigated by studying the surface reactivity of the growing calcium sulfate mineral faces via AFM force spectroscopy. This allows interaction forces between the deposit surface and different additive chemistries to be quantitatively determined in an oil-based environment, opening up methods for preventing deposition on engine surfaces. Unexpected, low adhesion values are obtained between polar additive head groups and the polar crystal deposit surface, a consequence of electrostatic repulsion. Thus, this work reveals key aspects related to the structure of charge in organic environments, an area still under much debate. The last chapter of this thesis switches focus to one of the key minerals responsible for engine deposit growth, calcium carbonate. Charged graphite interfaces are implemented to study their effects on the oriented nucleation and polymorphism of this crystal system, in the absence of defects and chemical functionalities. This highlights the significant role electrostatics play in nucleating high energy crystal planes and polymorphs, which is of huge importance for biomineralisation, and scale-prone, charged industrial surfaces. Overall, this thesis elucidates the unexplored properties of two highly relevant functionalised crystal growth interfaces, demonstrating their importance for preventing deposit growth, as well as their diverse application for the synthesis of high energy crystalline materials.

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4

Helalizadeh, Abbas. "Mixed salt crystallisation fouling." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/844179/.

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The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer and subcooled flow boiling conditions. It was assumed that the deposition process of calcium sulphate and calcium carbonate takes place in two successive events. These events are the combined effects related to transport phenomena and chemical kinetics. The effect of the extra deposition created on the heat transfer surface due to sub-cooled flow boiling was considered by inclusion of an enhancement factor. The newly developed model takes into account the effects of all important parameters on scaling phenomena and also considers the simultaneous precipitation and competition of various minerals in the scale formation process. Model predictions were compared with the measured experimental data when calcium sulphate and calcium carbonate form and deposit on the heat transfer surface simultaneously. While deviations ranging from 6% to 25% between model predictions and measured experimental data can be considered good in the context of such a complex process, fouling morphology is clearly a factor to be considered in more detail. This is particularly problematic in the context of more complex fouling solutions encountered in industry. Furthermore, the crystalline samples were analysed using Scanning Electron Microscopy, X- Ray Diffraction and Ion Chromatography techniques. Fractal analysis performed on Scanning Electron Microscopy photographs of the deposits was used to quantify deposit characteristics by introducing a new quantity called the fractal dimension.

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5

Emms, S. "Crystallisation of PFA glasses." Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/8485.

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Bibliography: leaves 79-81.
Glasses with various compositions, falling in the CaO-AI20rSi02 and MgO-CaOAI20rSi02 systems were made, using pulverised fuel ash and silica, hydrated lime, kaolin and magnesium carbonate. Titania or ferric oxide and chromia were used as nucleants. Various crystallisation heat treatments were carried out and the nucleation and crystallisation behaviour was studied. A minimum MgO:CaO was found to be necessary for bulk nucleation to occur. The activation energy for viscous flow decreased with increased MgO:CaO ratios. This was accompanied by an increase in the surface crystal growth rates and a decrease in the activation energy for surface crystal growth. Titania also lowered the activation energies for viscous flow and surface crystal growth and caused an increase in the surface crystal growth rates.

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6

Dincer, Tuna. "Mechanims of lactose crystallisation." Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/1958.

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Lactose is the major carbohydrate in milk. The presence of lactose in whey constitutes a significant pollution problem for dairy factories. At the same time, there is an increasing market for high quality crystalline lactose. The main problem of lactose crystallisation, compared to sucrose, which is also a disaccharide, is that it is very slow, unpredictable and cannot easily be controlled. Compared to sucrose crystallisation, which has been extensively studied, lactose crystallisation lacks the fundamental research to identify the mechanisms of growth and effect of additives. An important difference from most other crystal growth systems is that ([alpha]-lactose hydrate crystals never grow from a pure environment; their growth environment always contains beta lactose. [alpha]-lactose monohydrate crystallises much more slowly because of the presence of [beta]- lactose in all solutions. Although there have been some studies on growth rates and the effect of additives, there has not been any reported work on the fundamentals of lactose crystallisation and the mechanisms that operate on the molecular level. The aim of this thesis is to gain a greater understanding at the fundamental processes, which occur at the molecular level during the crystallisation of lactose, in order to improve control at a macroscopic level.The growth rates of the dominant crystallographic faces have been measured in situ, at three temperatures and over a wide range of supersaturation. The mean growth rates of faces were proportional to the power of between 2.5-3.1 of the relative supersaturation. The rate constants and the activation energies were calculated for four faces. The [alpha]-lactose monohydrate crystals grown in aqueous solutions exhibited growth rate dispersion. Crystals of similar size displayed almost 10 fold difference in the growth rate grown under identical conditions for all the faces. Growth rate dispersion increases with increasing growth rate and supersaturation for all the faces. The variance in the GRD for the (0 10) face is twice the variance of the GRD of the (110) and (100) faces and ten times higher than the (0 11) face at different supersaturations and temperatures. The influence of [beta]-lactose on the morphology of [alpha]-lactose monohydrate crystals has been investigated by crystallising [alpha]-lactose monohydrate from supersaturated DMSO ethanol solutions. The slowness of mutarotation in DMSO allowed preparation of saturated solutions with a fixed, chosen [beta]-lactose content. It was found that [beta]-lactose significantly influences the morphology of [alpha]- lactose monohydrate crystals grown from DMSO solution. At low concentrations of [beta]-lactose, the fastest growing face is the (011) face resulting in long thin prismatic crystals. At higher [beta]-lactose concentrations, the main growth occurs in the b direction and the (020) face becomes the fastest growing face (since the (011) face is blocked by [beta]-lactose), producing pyramid and tomahawk shaped crystals.Molecular modeling was used to calculate morphologies of lactose crystals, thereby defining the surface energies of specific faces, and to calculate the energies of interactions between these faces and [beta]-lactose molecules. It was found that as the replacement energy of [beta]-lactose increased, the likelihood of [beta]-lactose to dock onto faces decreased and therefore the growth rate increased. The attachment energy of a new layer of [alpha]-lactose monohydrate to the faces containing [beta]-lactose was calculated for the (010) and (011) faces. For the (0 10) face, the attachment energy of a new layer was found to be lower than the attachment energy onto a pure lactose surface, meaning slower growth rates when [beta]-lactose was incorporated into the surface. For the (011) face, attachment energy calculations failed to predict the slower growth rates of this face in the presence of [beta]-lactose. AFM investigation of [alpha]-lactose monohydrate crystals produced very useful information about the surface characteristics of the different faces of the [alpha]-lactose monohydrate crystal. The growth of the (010) face of the crystal occurs by the lateral addition of growth layers. Steps are 2 nm high (unit cell height in the b direction) and emanate from double spirals, which usually occurred at the centre of the face. Double spirals rotate clockwise on the (010) face, while the direction of spirals is counterclockwise on the (010) face. A polygonised double spiral, showing anisotropy in the velocity of stepswas observed at the centre of the prism-shaped a-lactose monohydrate crystals grown in the presence of 5 and 10 % [beta]-lactose.The mean spacing of the steps parallel to the (011) face is larger than those parallel to the (100) face, indicating higher growth rates of the (011 )face. The edge free energy of the (011) face is 6.6 times larger than the (100) face in the presence of 5% [beta]-lactose. Increase of [beta]-lactose content from 5% to 10 % decreases the edge free energy of the growth unit on a step parallel to the (011) face by 10 %. Tomahawk-shaped [alpha]-lactose monohydrate crystals produced from aqueous solutions where the [beta]-lactose content of the growth solution is about 60 % have shown clockwise double spirals as the source of unit cell high steps on the (010) face of the crystal. However , the spirals are more circular than polygonised, unlike the prism shaped crystals and the mean step spacing of the (011) face is less than the steps parallel to the (110) face, indicating the growth rate reducing effect of [beta]-lactose on the (011) face. The (100) face of the [alpha]-lactose monohydrate crystal grows by step advancement in relative supersaturations of up to 3.1. Steps are 0.8 nm high and parallel to the c rection. Above this supersaturation, rectangular shaped two-dimensional nuclei, 10 nm high, were observed. The (011) face of the crystal grown at low supersaturations (s= 2.1) displayed a very rough surface with no steps, covered by 4-10nm high and 100-200[micro]m wide formations. Triangular shaped macrosteps were observed when the crystal was grown in solutions with s=3.1. In situ AFM investigation of the (010) face (T = 20[degree]C and s = 1.18) has shown that growth occurs by lateral addition of growth units into steps emanated by double spirals.The growth rate of the (010) face from in situ AFM growth experiments was calculated to be 1.25 gm/min. The growth rate of crystals grown in the in situ optical growth cell under identical conditions was 0.69 pm/min. The difference in growth rates can be attributed to the size difference of seed c stals used. The (010) face of a [alpha]-lactosemonohydrate crystal grown at 22.4 C and s=1.31 displayed triangular-shaped growth fronts parallel to the (011) face. The steps parallel to the (O11) face grow in a triangular shape, and spaces between triangles are filled by growth units until the end of the macrosteps is reached. No such formations were observed on steps parallel to the (110) face. Formation of macrosteps, 4-6 nm high, emanating from another spiral present on the surface was also observed on the (010) face of a crystal grown under these conditions.

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7

Dincer, Tuna. "Mechanims of lactose crystallisation." Curtin University of Technology, School of Applied Chemistry, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=14562.

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Lactose is the major carbohydrate in milk. The presence of lactose in whey constitutes a significant pollution problem for dairy factories. At the same time, there is an increasing market for high quality crystalline lactose. The main problem of lactose crystallisation, compared to sucrose, which is also a disaccharide, is that it is very slow, unpredictable and cannot easily be controlled. Compared to sucrose crystallisation, which has been extensively studied, lactose crystallisation lacks the fundamental research to identify the mechanisms of growth and effect of additives. An important difference from most other crystal growth systems is that ([alpha]-lactose hydrate crystals never grow from a pure environment; their growth environment always contains beta lactose. [alpha]-lactose monohydrate crystallises much more slowly because of the presence of [beta]- lactose in all solutions. Although there have been some studies on growth rates and the effect of additives, there has not been any reported work on the fundamentals of lactose crystallisation and the mechanisms that operate on the molecular level. The aim of this thesis is to gain a greater understanding at the fundamental processes, which occur at the molecular level during the crystallisation of lactose, in order to improve control at a macroscopic level.
The growth rates of the dominant crystallographic faces have been measured in situ, at three temperatures and over a wide range of supersaturation. The mean growth rates of faces were proportional to the power of between 2.5-3.1 of the relative supersaturation. The rate constants and the activation energies were calculated for four faces. The [alpha]-lactose monohydrate crystals grown in aqueous solutions exhibited growth rate dispersion. Crystals of similar size displayed almost 10 fold difference in the growth rate grown under identical conditions for all the faces. Growth rate dispersion increases with increasing growth rate and supersaturation for all the faces. The variance in the GRD for the (0 10) face is twice the variance of the GRD of the (110) and (100) faces and ten times higher than the (0 11) face at different supersaturations and temperatures. The influence of [beta]-lactose on the morphology of [alpha]-lactose monohydrate crystals has been investigated by crystallising [alpha]-lactose monohydrate from supersaturated DMSO ethanol solutions. The slowness of mutarotation in DMSO allowed preparation of saturated solutions with a fixed, chosen [beta]-lactose content. It was found that [beta]-lactose significantly influences the morphology of [alpha]- lactose monohydrate crystals grown from DMSO solution. At low concentrations of [beta]-lactose, the fastest growing face is the (011) face resulting in long thin prismatic crystals. At higher [beta]-lactose concentrations, the main growth occurs in the b direction and the (020) face becomes the fastest growing face (since the (011) face is blocked by [beta]-lactose), producing pyramid and tomahawk shaped crystals.
Molecular modeling was used to calculate morphologies of lactose crystals, thereby defining the surface energies of specific faces, and to calculate the energies of interactions between these faces and [beta]-lactose molecules. It was found that as the replacement energy of [beta]-lactose increased, the likelihood of [beta]-lactose to dock onto faces decreased and therefore the growth rate increased. The attachment energy of a new layer of [alpha]-lactose monohydrate to the faces containing [beta]-lactose was calculated for the (010) and (011) faces. For the (0 10) face, the attachment energy of a new layer was found to be lower than the attachment energy onto a pure lactose surface, meaning slower growth rates when [beta]-lactose was incorporated into the surface. For the (011) face, attachment energy calculations failed to predict the slower growth rates of this face in the presence of [beta]-lactose. AFM investigation of [alpha]-lactose monohydrate crystals produced very useful information about the surface characteristics of the different faces of the [alpha]-lactose monohydrate crystal. The growth of the (010) face of the crystal occurs by the lateral addition of growth layers. Steps are 2 nm high (unit cell height in the b direction) and emanate from double spirals, which usually occurred at the centre of the face. Double spirals rotate clockwise on the (010) face, while the direction of spirals is counterclockwise on the (010) face. A polygonised double spiral, showing anisotropy in the velocity of stepswas observed at the centre of the prism-shaped a-lactose monohydrate crystals grown in the presence of 5 and 10 % [beta]-lactose.
The mean spacing of the steps parallel to the (011) face is larger than those parallel to the (100) face, indicating higher growth rates of the (011 )face. The edge free energy of the (011) face is 6.6 times larger than the (100) face in the presence of 5% [beta]-lactose. Increase of [beta]-lactose content from 5% to 10 % decreases the edge free energy of the growth unit on a step parallel to the (011) face by 10 %. Tomahawk-shaped [alpha]-lactose monohydrate crystals produced from aqueous solutions where the [beta]-lactose content of the growth solution is about 60 % have shown clockwise double spirals as the source of unit cell high steps on the (010) face of the crystal. However , the spirals are more circular than polygonised, unlike the prism shaped crystals and the mean step spacing of the (011) face is less than the steps parallel to the (110) face, indicating the growth rate reducing effect of [beta]-lactose on the (011) face. The (100) face of the [alpha]-lactose monohydrate crystal grows by step advancement in relative supersaturations of up to 3.1. Steps are 0.8 nm high and parallel to the c rection. Above this supersaturation, rectangular shaped two-dimensional nuclei, 10 nm high, were observed. The (011) face of the crystal grown at low supersaturations (s= 2.1) displayed a very rough surface with no steps, covered by 4-10nm high and 100-200[micro]m wide formations. Triangular shaped macrosteps were observed when the crystal was grown in solutions with s=3.1. In situ AFM investigation of the (010) face (T = 20[degree]C and s = 1.18) has shown that growth occurs by lateral addition of growth units into steps emanated by double spirals.
The growth rate of the (010) face from in situ AFM growth experiments was calculated to be 1.25 gm/min. The growth rate of crystals grown in the in situ optical growth cell under identical conditions was 0.69 pm/min. The difference in growth rates can be attributed to the size difference of seed c stals used. The (010) face of a [alpha]-lactosemonohydrate crystal grown at 22.4 C and s=1.31 displayed triangular-shaped growth fronts parallel to the (011) face. The steps parallel to the (O11) face grow in a triangular shape, and spaces between triangles are filled by growth units until the end of the macrosteps is reached. No such formations were observed on steps parallel to the (110) face. Formation of macrosteps, 4-6 nm high, emanating from another spiral present on the surface was also observed on the (010) face of a crystal grown under these conditions.

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8

Le, Corre Kristell S. "Understanding struvite crystallisation and recovery." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/1434.

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Struvite crystallisation from wastewater effluents is seen as an alternative to traditional biological and chemical phosphorus removal processes used widely in the wastewater treatment industry. It presents the advantage of not only removing phosphorus but also generating a compound that could be reused as a fertiliser. However the application of struvite crystallisation processes at full scale is not widespread due to the unknown economical value of the process and the product, the need of pH control, the necessity of long operational times to ensure quality of the product and the formation of crystal fines. Preliminary crystallisation experiments were carried out at laboratory scale to provide a better understanding of nucleation and growth processes, and identify how basic parameters such as pH, mixing energy, water chemistry or presence of foreign ions affected struvite crystallisation. Particular attention was paid to the quality (i.e. size, shape and purity) of the crystal formed. The results revealed that the presence of calcium ions in solution could alter struvite purity and even inhibit its formation. pH was also identified as a parameter of major impact on struvite crystal quality. Indeed, pH could either influence struvite purity or affect size of crystals formed. Further investigations in a purposely built reactor also revealed that if struvite crystallisation is relatively simple to achieve, the control of struvite quality and more particularly crystal size is complex. Results at pilot scale showed that reactor operation and struvite surface charge could be a limitation to its agglomerative properties, hence to the formation of larger crystals. To optimise struvite crystallisation and limit the problem of fines formation the present study has investigated two possible solutions: struvite fines recovery by coagulation or struvite crystallisation on seed materials. Struvite coagulation proved to be an efficient solution to remove and recover struvite fines rapidly through floc formation. Of the coagulant tested, polyDADMAC was the most effective resulting in the formation of flocs 10 times bigger than the initial size of crystals. With regards to crystallisation on seed materials, the results revealed that success of struvite attachment onto seeds in short contact times was only efficient when mixing energy in the reactor was limited. In that sense, the submersion of a metallic system in the reactor allowed excellent phosphorus removal and rapid struvite recovery in only 2 hours of operation.

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9

Adler, Ayal. "Crystallisation : for a large orchestra." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85219.

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This essay presents an analysis of Crystallisation, a composition for a large orchestra. The work consists of a single movement, with a duration of approximately 15 minutes.
The analysis focuses mainly on formal structure, pitch organization, texture and rhythm. Some of the main topics are: large-scale form and subdivisions of each section, thematic interrelations of the sections, central pitches, pitch collections, chord structure and interrelations between texture and rhythm.
Throughout the course of the work, the music closely follows an overall process of searching for a valid structure and "core". In realizing this process the music takes on a variety of devices, among them: various kinds of symmetry within texture and form; thematic relations between separate sections through variants and material transformation; a coherent pitch organization which contains structural pitches, symmetrical collections and three main groups of chords; a complex and carefully structured rhythmic organization.
The concluding section of this essay compares between some of the properties of a crystal and the structure of various parts in Crystallisation.

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10

Crispin, Matthew D. M. "Manipulation and crystallisation of glycoproteins." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426374.

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Jacobsen, Carsten. "The control of protein crystallisation." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484170.

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Thornley, Sarah. "Crystallisation from anisotropic polyethlene melts." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494778.

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Research was directed towards further understanding the process of templating, whereby the crystallisation of the bulk material (branched polyethylene) Is altered from unoriented to oriented after melt shear by mapping it on to a pre-existing minority structure (linear polyethylene). Due to the rotational component in shear flow It Is considered a weaker flow, as compared to elongatlonal flow, for providing chain extension. Removal of the rotational component might lead to higher levels of anisotropy being detected in the melt, thus aiding in the understanding of templating. This was achieved by utilising a custom-built channel die to impart plane-strain compression in the melt.

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Kaerger, Joerg Sebastian. "Controlled crystallisation of mesoscopic particles." Thesis, University of Bath, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425636.

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Howell, Linda. "Crystallisation and melting in polyhydroxybutyrate." Thesis, University of Birmingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442644.

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Phillipson, Kate. "Ageing and crystallisation of polycaprolactone." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6540/.

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Partially crystalline polycaprolactone stored at different temperatures well above the glass transition temperature is found to age with the development of further crystallinity and an increase in melting point, yield stress and elastic modulus with time. The changes in mechanical properties are accounted for by the increased crystallinity, and the increase in melting point to an increase in lamellae thickness. Over the temperature range studied, the rate of ageing increase with temperature and the dependence of stem length on the square root of storage time observed are both consistent with diffusion control and inconsistent with nucleation control. It is concluded that partially crystalline polycaprolactone ages by a continuation of the crystallisation at a rate determined by the storage temperature and by the mechanism occurring prior to ageing.

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Hayles-Hahn, Cameka. "Nanoseeds for pharmaceutical batch crystallisation." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24428.

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Homogeneous seed size and shape irregularities in batch crystallisation processes lead to variations in the crystal size distribution and crystal shape of active pharmaceutical ingredients (APIs). This thesis presents an extensive study into the tailoring of heterogeneous seeds to obtain reproducible mean crystal sizes and narrow crystal size distribution characteristics of the model product API paracetamol. Model heterogeneous seeds are primarily silica, and secondary seeds are zinc oxide and titanium dioxide. Synthesised silica seeds prepared according to the Stöber protocol were compared with purchased manufactured silica seeds. Characterisation techniques including light scattering, nitrogen sorption and zeta potential amongst others were used to confirm the physical and chemical characteristics of the heterogeneous seeds. Monodispersed product crystal size distribution was achieved with the purchased silica seeds 7nm to 1μm; with the microporous synthesised silica seeds; with the functionalised seeds and with the Janus functionalised seeds. All comparisons were made with respect to an unseeded control batch. The synthesised mesoporous silica seeds when used at loads greater than 0.50wt.% resulted in broad crystal size distributions. The synthesised mesoporous silica seeds demonstrate that when a broad pore size distribution is present, a detrimental effect on crystal size distribution control occurs. The synthesised microporous heterogeneous seeds with pore sizes less than 2nm lead to the greatest reduction in the mean crystal size out of all the silica seeds. Monodispersity of the crystal size distribution is shown to be independent of the functionality of the seeds investigated. The amine, methyl and fluoro functionalised seeds facilitate the growth of monodispersed product batch sizes with mean crystal sizes in the range of 92-200μm. A 'cut-off' fluoro functionalised seed size was observed at 1μm; where mean crystal sizes larger than 210μm were obtained. Here the competition between the paracetamol solute adsorption and electrostatic repulsions of the seed functionality is related to the product mean crystal size. An elongation of the primary paracetamol crystals was achieved with the synthesised mesoporous silica seeds, the methyl functionalised seeds and also with the commercially manufactured titanium dioxide seeds. Crystal growth inhibitions parallel to the pore width is one explanation for the effects of the mesoporous seeds. Significant agglomeration of the product crystals resulted from seed loads in the excess of 1.00wt.% of the purchased silica seeds, the synthesised mesoporous seeds, the fluoro functionalised seeds and in the presence of the synthesised zinc oxide seeds. These findings suggest that the seed hydrophilicity or the electronegativity exacerbate the agglomeration prone compound. Solution profile control close to the solubility curve was achieved with the synthesised mesoporous silica seeds and 0.50wt.% titanium dioxide seeds. The significance of the effect of hydrophobicity and local cluster entrapment of the heterogeneous seeds is investigated. In conclusion, the heterogeneous seed physical and chemical characteristics are found to play a similar role in determining the product mean crystal size, size distribution and crystal shape characteristics from batch crystallisation processes. The findings provide a framework for identifying potential key seed properties that can improve the quality and efficiency of batch crystallisation processes of APIs.

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Pagire, Sudhir Kashinath. "Novel methods for co-crystallisation." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/12841.

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The research described in this dissertation mainly covers the development of novel technologies for co-crystallisation along with the discovering of plumbagin co-crystal and thermodynamic interrelationship between the co-crystal polymorphs. Co-crystallisation is a fast growing field in the area of crystal design and has shown potential advantages in the field of pharmaceutical. Currently, many research groups are working on the development of new technologies for the synthesis of pure and stoichiometrically controlled co-crystals. In present study, three novel technologies have been developed for co-crystallisation, which include microwave assisted co-crystallisation, spherical crystallisation and microwave assisted sub-critical water processing. The microwave assisted co-crystallisation is a slurry based technology where, effects of drug solubility and dielectric properties of the solvent were investigated using caffeine / maleic acid as a model co-crystal pair. The mechanism of co-crystallisation under microwave irradiation has been proposed. The co-crystals of plumbagin with improved solubility were obtained with the coformers such as hydroquinone, resorcinol and urea using microwave assisted co-crystallisation technique. The spherical crystallisation technology was developed for co-crystallisation of carbamazepine / saccharin co-crystal pair and demonstrated its application for polymorphic control and as a potential technique for the purification of desired crystal form through surface energetic based separation. The thermodynamic interrelationship between Form I and Form II of carbamazepine / saccharin co-crystal was studied using different thermodynamic tests. The results obtained suggest that the carbamazepine / saccharin co-crystal polymorphs are monotropic. Microwave assisted sub-critical water processing has been explored as a green technology for the synthesis of co-crystals. Carbamazepine / saccharin co-crystal pair has been used as a model pair and effects of processing variables on the resulting crystal form and degradation of an API have been studied.

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Zhu, Jing. "Polymer-mediated crystallisation of proteins." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/27707/.

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Proteins are the functional machines of nature and play an essential role in life. Understanding the structure and function of proteins is central to numerous areas of science and technology, including biotechnological, pharmaceutical and chemical industries. Protein crystals are an important objective for many researchers, but even though there are many examples of protein crystals reported, there are still many uncertainties in controlling the crystallisation process. In addition, while protein crystals have mostly been obtained for characterisation purposes, there are other applications where defined assemblies of proteins, either crystals or self-assembled protein nanoparticles, are desirable. These include industrial biocatalysis, therapeutic protein formulations, and even energy-harvesting systems. Accordingly, there remains a high demand for well-defined protein crystals or nanoscale aggregates. A variety of techniques have been used to produce protein crystals, the typical strategy involves the addition of nucleants surface, or surface-active materials into the crystallisation solution. Solution ‘additives’ of diverse types have proven crucial in the control of protein crystallisation. These additives can act via multiple roles in a crystallisation process, such as by enhancing intermolecular contacts between protein macromolecules, or disrupting unfavourable intermolecular association, or diminishing interactions between protein and solvent. Synthetic polymers are important additives for protein crystallisation control as there are many possible chemistries which can be introduced into the backbone and side-chains, giving a very wide range of functional behavior. However, because there are so many factors which can affect crystallisation, many of which are still poorly understood, to date only a very few classes of polymers have been studied as additives for protein crystallisation. Moreover, the mechanisms governing their interactions with protein crystals or surrounding solvent are elusive. In the study presented here, we show that polymers designed with varying degrees of charge, molecular weight and backbone structure influenced the crystallisation of three target proteins: hen-egg white lysozyme (HEWL); concanavalin A (Con A); and bovine liver catalase (BLC). Polymers were prepared as ‘additives’ into protein solution to influence the proteins crystallisation process, leading to changes in size, habit, morphology and even polymorph of the final crystals. A simple model linking polymer structure and charge to protein isoelectric point (pI) and crystallisation rate is proposed.

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Shah, Umang Vinubhai. "3D nanotemplates for protein crystallisation." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/10681.

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This thesis presents the first experimental investigations into the combined effect of nanoscale surface porosity, narrow pore size distribution and surface chemistry, on nucleation and crystallisation of proteins. Co-operative self assembly of surfactants and silica was applied to prepare 3D nanotemplates with pore diameter 3.5±1.0nm, 5.5±1.5nm, 11.0±3.0nm, 16.0±3.0nm and 22.0±5.0nm. Post synthesis functionalisation was used to graft surface with -OH, -NH2, -CF3, -C6H5, - Cl and -CH3 functional groups. The relationship between 3D nanotemplate, N2 sorption and TEM pore diameter, XPS surface composition, wettability, surface charge and protein physicochemical properties was investigated, resulting in a coherent understanding of the combined effect of nucleant surface porosity and surface chemistry on protein crystallisation. The protein systems investigated for crystallisation include lysozyme, thaumatin, trypsin, albumin, concanavalin A, catalase and ferritin; varying in molecular weight from 14kDa – 450kDa and hydrodynamic diameter ~3-20nm. Crystallisation of proteins was found to be strongly dependent on 3D nanotemplate pore size. The 3D nanotemplate with a pore diameter similar to the protein’s hydrodynamic diameter (Dh) was found to be successful in preferential crystallisation, e.g. albumin (Dh=~5nm) and catalase (Dh=~10nm) was crystallised only on 5.5±1.5nm and 11.0±3.0nm 3D nanotemplates respectively. Here, we report a direct correlation between protein hydrodynamic diameter and 3D nanotemplate pore diameter, key for controlling protein nucleation. The correlation has been experimentally validated for all protein systems investigated. The concept of preferential crystallisation was further developed to investigate the applicability of this methodology for the separation of a target protein from a protein mixture. A solution of two proteins; porcine pancreatic lipase and RNAse was selected for this separation by crystallisation. Lipase (Dh=~4.5nm) and RNAse (Dh=~1.5nm) crystals were preferentially obtained with 5.5±1.5nm and 3.5±1.0nm 3D nanotemplates respectively. Furthermore, crystallisation of lipase from a commercially available crude source, (purity ~20%) containing a mixture of lipase, amylase and protease, was also achieved on the surface of the 5.5±1.5nm 3D nanotemplate. The significance of the work here is the demonstration that only specific nucleant surfaces with narrow pore size distribution can preferentially crystallise a target protein from a protein mixture, which is not possible with nucleants of broad pore size distribution, reported to be most suitable candidate for “universal nucleant”. Crystals of four out of the seven well studied proteins (lysozyme, albumin, concanavalin A and catalase) were obtained at lower protein concentration, whilst thaumatin was crystallised at par protein concentration but 3× lower precipitant concentration, on the surface of 3D nanotemplates functionalised with -OH, -CH3 and -NH2 functional groups. Here, we report that a reduction of 50- 92% protein concentration compared to the lowest reported literature values was achieved with the use of the 3D nanotemplates. As crystallisation was achieved for all seven protein systems at protein concentrations in the range of 2-20mg/mL, this approach can be used to engineer surfaces for preferential crystallisation of a target protein directly from industrial bioreactor broths. In summary, the findings of this thesis offer a first systematic approach for controlling the nucleation and crystallisation of biological macromolecules. The use of 3D nanotemplates offers the possibility of crystallising complex proteins (e.g. enzymes, antibodies, protein complexes, DAbs, MAbs) for structural determination and also novel crystallisation routes for downstream bioseparations.

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Kirkwood, Jobie Samuel. "Analysis of protein crystallisation parameters." Thesis, University of York, 2015. http://etheses.whiterose.ac.uk/9656/.

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Proteins are biochemical molecules that are essential for life processes. Their function is linked to their structure and so it follows an understanding of their structure will assist in an understanding of their function. The predominant method of solving protein structures is X-ray crystallography and for this a protein crystal is required. The process of obtaining a crystal is amongst the phases of the structure determination process with the highest rates of attrition. Analyses are performed throughout this thesis, which are intended to help improve output for this bottleneck. It has been possible to develop a method to determine pH using a spectrophotometer and acid-base indicator in an accurate, rapid and efficient manner. A method for predicting the pH of buffered solutions has also been developed and these predicted pH values are linked to the isoelectric point of a protein sequence. The isoelectric point is in turn used in classification, along with many other features, to determine a protein's propensity to crystallise. Finally, the most prevalent and successful chemical species in crystallisation are explored, compared and linked. These chemicals are used to design a new crystallisation screen.

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Pagire, Sudhir K. "Novel Methods for Co-crystallisation." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/12841.

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Al-Marri, Mohd Jaber F. A. "Modelling the solution crystallisation of L-gluatmic acid as prepared via reactive and cooling crystallisation." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545682.

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Fjellstedt, Carl Jonas. "Crystallisation Processing of Al-base Alloys." Doctoral thesis, KTH, Production Engineering, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3201.

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Moorehead, Robert David. "Crystallisation in fluorapatite-fluorphlogopite glass ceramics." Thesis, University of Salford, 2011. http://usir.salford.ac.uk/26825/.

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Apatite based glass-ceramics are some of the most bioactive materials found to date. They do not require fibrous encapsulation and bond to bone directly through an apatite layer. Apatite based glass-ceramics exhibit relatively poor biaxial flexural strength, hence limiting their applications to non-load bearing implants. The addition of mica results in a material that is highly machinable, and provided that a suitable interlocking microstructure can be produced, the strength will be increased. The aim of this work is to investigate how altering the heat treatment affects the crystallisation and the final mechanical properties of three different compositions of glass-ceramic. The glass system studied is the ternary glass system; barium fluorphlogopite (Bao.sMgafSiaAlOiojFz), fluorapatite (CaiofPO^eFz) and cordierite (MgzAUSisOis). The three compositions differ by the mol% of fluorapatite forming feedstock in the precursor glass. Glass-ceramics formed by heat-treating a glassy precursor are investigated using differential scanning calorimetry, kinetic neutron diffraction and scanning electron microscopy. The mechanical properties of the samples are characterised by their biaxial flexural strength and Vickers hardness. The phases formed and the microstructures of the samples are linked to the mechanical properties and an assessment of the final material's implant suitability is made.

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Kuo, Anling. "Ion channel crystallisation for structural studies." Thesis, University of Oxford, 2004. https://ora.ox.ac.uk/objects/uuid:34c71712-d16b-49e5-ad37-dd4cd7fd9442.

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Ion channels control the movement of ions allowing specific ions to pass across biological membranes. This apparently simple process is used to control many essential physiological processes including the generation and propagation of neuronal excitation, regulation of insulin secretion, heartbeat and cell volume. Ion channels are able to do this by having multiple means of controlling the opening and closing of the ion conduction pathway. Several recent ion channel structures have shed light on the important process of ion selectivity as well as providing clues on channel gating. However, it is not yet completely clear how ion channels control the passage of ions across the membrane. My work is centred on understanding the gating process through structural analysis mostly using X-ray crystallography. In order to get to this point, crystals of the target ion channels need to be grown. This thesis presents four projects that were aimed at developing the techniques for over-expression, purification and crystallisation of ion channels or transporters making them amenable for structural studies. One of the difficult steps in the structure determination pathway is obtaining well-ordered crystals of the target membrane protein. Crystals of the EcCLC channel (now found to be a transporter) from E. coli were initially unacceptable for structure determination. It was shown that the process of dehydration improved the quality and diffraction limit of the EcCLC crystals. This simple method provides a possible procedure for improving the resolution limit of soluble and membrane protein crystals. Inward rectifier potassium channels (Kir channels) are a distinct subfamily that preferentially allows K⁺ ions to move into the cell. Two bacterial homologues of Kir channels, KirBac1.1 and KirBac3.1, were crystallised in 3-D and 2-D forms, respectively. As the crystal structure revealed the full-length model provided an excellent starting point for understanding the gating process in these channels. The 3-D structure of KirBac1.1 was captured in the closed state. This K⁺ channel prevents ion movement by using hydrophobic residues to occlude the ion conduction pathway, altering the conformation of selectivity filter, misaligning the pore helices and decreasing the volume of the cavity. The 2-D projection maps of KirBac3.1 were obtained in both closed and a potentially open conformations. These two maps provided evidence as to how the structural elements of the inner, outer, slide helices and the C-terminal domains change relative to one another as the channel moves between these two gating states. These motions were modelled as rigid body movements. They included bending of the inner helices, a rotation of the outer helices as they straighten in the membrane, translocation of the slide helices and C-terminal domain rotations. It is hoped that the information gained from these projects, the plasmids construction, the expression systems and the protocols that were established for crystallisation of the ion channels and transporter will provide guidelines for future structural studies of membrane proteins.

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Moldoveanu, Georgiana A. "Crystallisation of inorganic compounds with alcohols." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85627.

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Crystallisation, one of the oldest unit operations, is of major economic importance in the hydrometallurgical industry for the separation and/or production of inorganic metal compounds in the form of good quality crystals, both in terms of purity and size. However, industrial crystallisation techniques usually have high energy requirements (e.g. evaporative crystallisation) and the residual solutions are often extremely corrosive, resulting in elevated operating and maintenance costs. Additionally, the majority of industrial crystallisation methods do not render to the appropriate supersaturation control, therefore the produced salts are agglomerates of fine crystallites with heavy solution entrainment and contamination.
In this work, the Solvent Displacement Crystallisation (SDC) technique is investigated as an attractive alternative to the conventional crystallisation methods. SDC involves the addition of low-boiling point, water-miscible organic solvents (MOS) to aqueous solutions to cause salt precipitation based on the salting out effect. The crystals are separated by filtration whereas the solvent is subsequently recovered for reuse by low-temperature distillation. The present work was initiated with the main objective to develop a solid scientific understanding of the SDC process and propose specific applications to hydrometallurgical systems of practical interest.
Criteria for the selection of organic solvents with suitable physical and chemical properties have been established and various compounds screened to determine their amenability to SDC; 2-propanol was selected as an effective salting out agent to cause precipitation of most metallic sulphates of practical interest from acidic solutions and opted for use in further studies. Differences in crystallisation behaviour among the various metal sulphates were attributed to differences in hydration energy (the energy required for a hydrated ion to be separated from its bound water).
None of the tested metal chlorides could be successfully separated from HCl-H2O system with 2-propanol. This was explained in terms of enhanced metal chlorides solubilities in non-aqueous solvents relative to water by formation of chloro-complexes of larger stability constants. The preferential formation of chloro-complexes in mixed aqueous and organic solvents is the result of the almost linear drastic increase in the activity of Cl - with mole fraction organic.
Successful examples of using the SDC method in conjunction with an industrial process involve precipitation of NiSO4·6H2O from copper electrorefining spent electrolytes, residual sulphate removal as gypsum (CaSO4·2H2O) in chloride leaching processes and ZnO separation/NaOH regeneration in the system Na2ZnO2, - NaOH - H2O. By maintaining a low supersaturation (i.e. controlled addition of the solvent to the electrolyte) and heterogeneous crystallisation conditions (use of seed/product recycling), crystal growth is favoured while impurity uptake/contamination is minimised.

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Aina, Adeyinka Temitope. "In situ monitoring of pharmaceutical crystallisation." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12460/.

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Using confocal Raman spectroscopy/microscopy, we have monitored pharmaceutical crystallisation 'in situ' in three model (well characterised polymorphic systems) Active Pharmaceutical Ingredients (APIs) and one previously unstudied system where polymorphism had not being reported prior to this study: flufenamic acid, a Non Steroidal Non-Inflammatory Drug (NSAID); nifedipine, an antihypertensive; tolbutamide, used in the treatment of type II diabetes; and imipramine hydrochloride, an antidepressant respectively. Constrained crystallisation from the solid amorphous state was utilised to kinetically trap polymorphs via the Ostwald's rule of stages. Particular emphasis was placed on the phonon-mode/low wavenumber region (4-400cm-1) of the Raman spectral window (this region provides useful information about lattice environment). In all cases our results from the Raman experiments were complemented with similar experiments using Differential Scanning Calorimetry (DSC) and Variable Temperature X-ray Powder Diffraction (VTXRPD). To reduce data complexity, principal component analysis was deployed and found to be extremely effective. In chapter two, a multi-technique study of flufenamic acid (FFA) was carried out which served as a groundwork for later chapters. A solid-solid transformation between two forms of FFA (forms I and III) was observed, due to the abrupt nature of this transition, the 'Lindemann vibrational catastrophe' was envisaged as a possible mechanism for the transformation. Using FFA as a test case in chapter three, polymorphic transformations was monitored in both FFA forms I and III using in situ Raman spectroscopy (as well as VTXRPD) by adopting the constrained crystallisation approach. The approach showed excellent promise (with the XRPD patterns of FFA form II and one unknown form uncovered) and was further explored in later chapters using a variety of pharmaceutical materials. While in chapter four, the interconversion between the different polymorphs of nifedipine was studied using the constrained crystallisation approach monitored using in situ Raman spectroscopy (together with VTXRPD and DSC), our results compared favourably well with those previously published in literature. We also reported for the first time the phonon-mode Raman spectral for this system as earlier publications focussed only on the 'traditional' fingerprint region. Similarly in chapter five, in situ Raman spectroscopy was also used to monitor the polymorphic transformations in tolbutamide (using the constrained crystallisation approach), results from the Raman analysis was compared with those obtained from VTXRPD and found to be in agreement. Thus further showing that Raman spectroscopy combined with the constrained crystallisation approach is a veritable tool for monitoring polymorphic transitions. In chapter six, preliminary results (Raman/XRPD/DSC) showed for the first time that imipramine hydrochloride exhibits polymorphism, with the possibility of at least two new polymorphs. Combination of state of the art spectroscopic techniques with appropriate statistical methods, X-ray powder diffraction and DSC was shown to be an extremely effective approach to investigating and characterising polymorphism in drugs, often using only milligram or sub-milligram sample quantities. Lastly in chapter seven, the novel technique of Transmission Raman Spectroscopy (TRS) was employed in carrying out a quantitative study of polymorphic content in a model pharmaceutical formulation and the results obtained compared with those from traditional backscattering geometry. The transmission method is shown to provide a true bulk measurement of the composition, being unaffected by systematic or stochastic sub-sampling issues that can plague traditional backscattering geometries.

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Capes, J. S. "Pharmaceutical polymorphs : crystallisation, stabilisation and delivery." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597280.

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The work presented here describes a novel method for crystallising the metastable polymorph of paracetamol from an evaporating aqueous solution. Generally this form cannot be obtained from solution as it undergoes a rapid solvent-mediated phase transformation to the more stable form. In this new method it is found that the metastable polymorph nucleates and grows at the edge of the meniscus. The crystals form here due to favourable surface tension forces and a localised concentration increase. The metastable crystal is then unable to transform to the more stable form because the crystals are effectively removed from the solvent as the level of the solution drops away from this region as evaporation proceeds. The ability to obtain metastable polymorphs is particularly interesting as they can offer enhanced pharmaceutical properties such as increased dissolution rates. Therefore, the second part of this work looks at incorporating metastable drug crystals directly into delivery devices without further processing. This concept involves incorporating a crystallisation ‘dish’ into a dosage device in the form of an individual pore in a substrate or scaffold, so that the required crystal form can be grown in situ. A manufacturing method has been developed to produce polymer scaffolds with a very controlled pore structure by using sugar spheres as a regularly shaped solid porogen. In addition, an image processing technique, based on X-ray microtomography data, is used to fully characterise the resultant scaffolds.

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Gao, Wei. "Oxidation and crystallisation of amorphous alloys." Thesis, University of Oxford, 1988. http://ora.ox.ac.uk/objects/uuid:8a2a2323-24e2-4bdc-9b3e-4a22f9ec45ae.

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Amorphous alloys have a range of desirable ferromagnetic, electrical, mechanical and chemical properties. For instance, the application of Fe-based soft ferromagnetic amorphous alloys as transformer core materials can cut the transformer core losses to about 1/4, with considerable energy saving. However, during manufacture, heat treatment and in service, amorphous alloys may need to be exposed to moderately high temperatures for a period of time, with possible degradation caused by oxidation and crystallisation. There has been almost no previous study of oxidation behaviour and the relationship between oxidation and crystallisation in amorphous alloys. Eight important amorphous alloys and an industrial crystalline silicon steel have been studied in the present work; amorphous Fe78Si9Bl3, Fe40Ni40B20, Fe40Ni40P14B6, Co58NilOFe5SillB16, Fe32Ni36Crl4P12B6, Co66Fe4NilSil5B14, Co76Fe2Mn4Si6B12 and Ni78Si8B14, and crystalline Fe94Si6. A combination of thermogravimetry, optical and electron microscopy, electron probe microanalysis, X-ray diffractometry and differential scanning calorimetry has been used to investigate the oxidation and crystallisation kinetics, oxide structure and composition, oxidation and crystallisation mechanisms and the effect of crystallisation on the oxidation behaviour. The results show that the oxidation resistance at 350 C in air increases in the order Fe40Ni40- P14B6 < Fe94Si6 < Co66Fe4NilSil5B14 < Co58NilOFe5SillB16 < Co76MnFe2- Si6B12 < Fe40Ni40B20 < Si78Si9B13 < Ni78Si8B14 < Fe32Ni36Crl4P12B6. Most of the amorphous alloys obey a parabolic oxidation rate law, but the oxidation kinetics, oxide growth mechanism and resulting oxide structure change sharply when crystallisation takes place in the amorphous alloys. Amorphous Fe78Si9B13 and Fe40Ni40B20 have better oxidation resistance than the corresponding crystalline alloys, while amorphous Fe40Ni40P14B6 and Co58NilOFe5Sil1B16 have poorer oxidation resistance than the crystalline counterparts. Most of the crystalline alloys also obey a parabolic oxidation rate law, except for the crystalline Co based alloys and Fe40Ni40B20, which obey a logarithmic rate law. In most cases, the amorphous and crystalline alloys oxidise to form a fine-scale multiphase oxide scale, except for amorphous Fe40Ni40P14B6, which oxidises to form a whisker-like thick layer of Fe203- In general, ion diffusion through fast transport paths such as grain boundaries and dislocations is the rate controlling process for oxide growth. Different oxidation kinetics and oxide growth mechanisms in amorphous and crystalline alloys of the same composition are caused by micro-chemical segregation of the alloying elements during crystallisation.

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Carstensen, Angela. "Clathrate hydrate and N-alkaline crystallisation." Thesis, King's College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400582.

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Anandamanoharan, P. "Isolation of enantiomers via diastereomer crystallisation." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/19315/.

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Enantiomer separation remains an important technique for obtaining optically active materials. Even though the enantiomers have identical physical properties, the difference in their biological activities make it important to separate them, in order to use single enantiomer products in the pharmaceutical and fine chemical industries. In this project, the separations of three pairs of diastereomer salts (Fig1) by crystallisation are studied, as examples of the ‘classical’ resolution of enantiomers via conversion to diastereomers. The lattice energies of these diastereomer compounds are calculated computationally (based on realistic potentials for the dominant electrostatic interactions and ab initio conformational energies). Then the experimental data are compared with the theoretical data to study the efficiency of the resolving agent. All three fractional crystallisations occurred relatively slowly, and appeared to be thermodynamically controlled. Separabilities by crystallisation have been compared with measured phase equilibrium data for the three systems studied. All crystallisations appear to be consistent with ternary phase diagrams. In the case of R = CH3, where the salt-solvent ternaries exhibited eutonic behaviour, the direction of isomeric enrichment changed abruptly on passing through the eutonic composition. In another example, R = OH, the ternaries indicated near-ideal solubility behaviour of the salt mixtures, and the separation by crystallisation again corresponded. Further, new polymorphic structures and generally better structure predictions have been obtained through out this study. In the case of R = CH3, an improved structure of the p-salt has been determined. In the case of R = C2H5, new polymorphic forms of the n-salts, II and III, have been both discovered and predicted. This work also demonstrates that chemically related organic molecules can exhibit different patterns of the relative energies of the theoretical low energy crystal structures, along with differences in the experimental polymorphic behaviour. This joint experimental and computational investigation provides a stringent test of the reliability of lattice modelling to explain the origins of chiral resolution via diastereomer formation. All the experimental and computational works investigated in this thesis are published (see APPENDIX 1).

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Robinson, Sean Wade. "Co-crystallisation with 1,2,3,5-dithiadiazolyl radicals." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20149.

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Sanzida, Nahid. "Iterative learning control of crystallisation systems." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14981.

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Under the increasing pressure of issues like reducing the time to market, managing lower production costs, and improving the flexibility of operation, batch process industries thrive towards the production of high value added commodity, i.e. specialty chemicals, pharmaceuticals, agricultural, and biotechnology enabled products. For better design, consistent operation and improved control of batch chemical processes one cannot ignore the sensing and computational blessings provided by modern sensors, computers, algorithms, and software. In addition, there is a growing demand for modelling and control tools based on process operating data. This study is focused on developing process operation data-based iterative learning control (ILC) strategies for batch processes, more specifically for batch crystallisation systems. In order to proceed, the research took a step backward to explore the existing control strategies, fundamentals, mechanisms, and various process analytical technology (PAT) tools used in batch crystallisation control. From the basics of the background study, an operating data-driven ILC approach was developed to improve the product quality from batch-to-batch. The concept of ILC is to exploit the repetitive nature of batch processes to automate recipe updating using process knowledge obtained from previous runs. The methodology stated here was based on the linear time varying (LTV) perturbation model in an ILC framework to provide a convergent batch-to-batch improvement of the process performance indicator. In an attempt to create uniqueness in the research, a novel hierarchical ILC (HILC) scheme was proposed for the systematic design of the supersaturation control (SSC) of a seeded batch cooling crystalliser. This model free control approach is implemented in a hierarchical structure by assigning data-driven supersaturation controller on the upper level and a simple temperature controller in the lower level. In order to familiarise with other data based control of crystallisation processes, the study rehearsed the existing direct nucleation control (DNC) approach. However, this part was more committed to perform a detailed strategic investigation of different possible structures of DNC and to compare the results with that of a first principle model based optimisation for the very first time. The DNC results in fact outperformed the model based optimisation approach and established an ultimate guideline to select the preferable DNC structure. Batch chemical processes are distributed as well as nonlinear in nature which need to be operated over a wide range of operating conditions and often near the boundary of the admissible region. As the linear lumped model predictive controllers (MPCs) often subject to severe performance limitations, there is a growing demand of simple data driven nonlinear control strategy to control batch crystallisers that will consider the spatio-temporal aspects. In this study, an operating data-driven polynomial chaos expansion (PCE) based nonlinear surrogate modelling and optimisation strategy was presented for batch crystallisation processes. Model validation and optimisation results confirmed this approach as a promise to nonlinear control. The evaluations of the proposed data based methodologies were carried out by simulation case studies, laboratory experiments and industrial pilot plant experiments. For all the simulation case studies a detailed mathematical models covering reaction kinetics and heat mass balances were developed for a batch cooling crystallisation system of Paracetamol in water. Based on these models, rigorous simulation programs were developed in MATLAB??, which was then treated as the real batch cooling crystallisation system. The laboratory experimental works were carried out using a lab scale system of Paracetamol and iso-Propyl alcohol (IPA). All the experimental works including the qualitative and quantitative monitoring of the crystallisation experiments and products demonstrated an inclusive application of various in situ process analytical technology (PAT) tools, such as focused beam reflectance measurement (FBRM), UV/Vis spectroscopy and particle vision measurement (PVM) as well. The industrial pilot scale study was carried out in GlaxoSmithKline Bangladesh Limited, Bangladesh, and the system of experiments was Paracetamol and other powdered excipients used to make paracetamol tablets. The methodologies presented in this thesis provide a comprehensive framework for data-based dynamic optimisation and control of crystallisation processes. All the simulation and experimental evaluations of the proposed approaches emphasised the potential of the data-driven techniques to provide considerable advances in the current state-of-the-art in crystallisation control.

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Nicholson, Catherine Emma. "Crystallisation in emulsion and microemulsion systems." Thesis, Durham University, 2006. http://etheses.dur.ac.uk/1298/.

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The use of emulsions as an aid to the study of crystallisation has long been known. However, the exploitation of this technique has not yet been realised to its full potential. The various conditions that can be generated at, or near, an interfacial region provide a wide range of possibilities for the controL and probing of crystallisation mechanisms. In this thesis, the effect of the interfacial curvature is considered for the case of ice crystallisation within water-in-oil emulsions. The use of a known ice nucleator, heptacosanol, acting as a co-surfactant enables the effect of a reduced epitaxial match to be monitored, with decreasing water pool diameter. The extreme case where the water pool does not contain enough material to form a crystalline nucleus such that ~G ~ 0 on complete crystallisation is found. This demonstrates for the first time that a direct experimental measurement of the critical nucleus size is possible. The use of non-ionic surfactants allows emulsions to phase invert from water-in-oil to oil-in-water upon cooling, and on passing through the phase inversion, ultra low interfacial tensions are obtained. At the phase inversion, crystallisation by the surfactant layer is found to be greatly inhibited, even at high solute supersaturations for glycine and L-asparagine emulsions. Hence we achieve anomalous crystallization behaviour, with crystallisation achieved both on cooling and heating from the same system. Another unique effect characterised is that of oil droplet inclusion into a single crystal. The highly polar octanoic acid oil phase adheres to the growing glycine crystal so strongly that crystal growth proceeds around the droplet without disruption to the overall resulting crystal to produce macroporous crystals. Where growth rates are uneven, highly fenestrated single crystalline structures result. Upon reducing the oil droplet diameter, dendritic morphologies, highly unusual for such low supersaturations of glycine, are formed. Moreover, the surfactant mixture also controls the polymorph produced, and reproducibly yields the desired ~-glycine form.

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Back, Kevin. "The crystallisation of conformationally flexible molecules." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/the-crystallisation-of-conformationally-flexible-molecules(e00131ab-f91f-4bc9-902b-421e4d70fd74).html.

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Crystallising large, flexible molecules, which are becoming more common in pharmaceutical development, often presents significant challenges for chemists and particle scientists. These difficulties are sometimes attributed to the flexibility of the molecule, and the existence of multiple conformers in solution. Structurally related impurities, frequently present when crystallising these materials, can also impact on growth and habit, and both these aspects are considered in this thesis. This work considers two pharmaceutical compounds, a relatively small but nonetheless flexible molecule, ethenzamide, and a precursor of Amprenavir, a much larger molecule. Both compounds typically grow as thin needles in a wide variety of solvents, and effort was required to grow suitable crystals for structure determination. Ethenzamide has an unusual structure, the amide group being out-of-plane relative to the ring, while in all known co-crystals of the compound, including three new co-crystal structures determined in this work, it has a planar structure with an intramolecular hydrogen bond not seen in the single component crystal. Theoretical structure generation calculations suggest a second polymorph with a planar conformation may exist, though a screen has not found any further solid phases. ab initio work suggests the planar conformation is the stable arrangement in vacuo. Several structures for the Amprenavir intermediate have been determined, as an ethanol solvate, a methanol solvate and a hydrate. A phase diagram has been measured in the industrial solvent mix, and the nucleation and growth properties of this molecule, both pure and in the presence of several structurally related impurities, have been measured. The Cambridge Structural Database has been searched for similar structures, and conformational searches have been carried out for both molecules, using vacuum phase ab initio energy calculations. Infrared spectroscopy has been used to investigate solution phase structure. These theoretical and practical studies will try to relate conformational properties to crystallisation behaviour.

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Mo^n, Dyfrig. "Fullerene crystallisation in Fullerene/Polymer bilayers." Thesis, Swansea University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678620.

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Lee, Phillip Alan. "Control of crystallisation using surface topography." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17568/.

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The purpose of this research project was to realise the control of crystallisation using surface topography. Calcium carbonate crystallisation was primarily used as this is a model system for crystallisation studies. The first experimental chapter involves the precipitation of calcium carbonate on a plasma-treated poly(dimethylsiloxane) (PPDMS) substrate. Exposure to atmospheric air-plasma results in oxidation of the surface of the poly(dimethylsiloxane), causing a superficial silica-like (SiOx) surface layer to form. Cracks in this surface, which arise because of its rigidity compared to the underlying bulk, were found to act as effective nucleation sites for calcium carbonate precipitation. Crystals were often observed only at the cracks and were absent elsewhere on the substrate. The surface chemistry was altered using a carboxylate terminated alkylthiol self-assembled monolayer (SAM), formed from the monomer 16-mercaptohexadecanoic acid. The presence of this monomer on the PPDMS substrate caused a significant increase in crystal population and enhanced the localising effect of the cracks. Further control of crystallisation was achieved by varying the initial ion ratio (Ca2+:CO32-) and by the presence of magnesium ions in solution. The substrate also proved effective at causing the localised precipitation of other inorganic materials: strontium carbonate, barium carbonate, manganese carbonate, basic copper carbonate and calcium oxalate. Through the application of contact masks or a tensile stress during plasma-treatment, it was possible to control the distribution of the cracks across the surface and therefore pattern the crystallisation of calcium carbonate. The second research chapter is a quantitative analysis of the system discussed in the first chapter. Here, an image analysis software, ImageJ, was used to obtain data from electron micrographs of the PPDMS substrate after crystallisation. Calcium carbonate had been precipitated on the PPDMS substrate once the surface chemistry had been modified using a variety of differently terminated alkylthiol SAMs. The research revealed that not only is it possible to control crystal populations at the surface features, but also the crystal polymorph. In the third research chapter, silicon wafers that had been spincoated with reduced-graphene oxide were used as substrates for calcium carbonate precipitation. Interestingly, the vast majority of crystals that had formed on these wafers were aragonite, a metastable phase of calcium carbonate. In order to understand why this was so, a series of investigations followed that were aimed at elucidating if it was a topographical effect or due to the presence of impurities. The data suggested that the large proportion of aragonite was due to topographical effects. The final research chapter involved cleanroom microfabrication techniques common to the semiconductor industry to construct surface structures on silicon wafers that were used as substrates. Crystallisation was locallised to these features, proving that it is possible to design surface topographies that can be used to control crystallisation.

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38

Tosi, Giovanna <1979&gt. "Macromolecular crystallography: crystallisation and structural determination." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1625/1/TESI_GT.pdf.

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39

Tosi, Giovanna <1979&gt. "Macromolecular crystallography: crystallisation and structural determination." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1625/.

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40

Penha, Frederico Marques. "Comportamento do sistema NaCI-KCI-H2O em cristalização simultânea." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-19092018-074356/.

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No que diz respeito às águas residuais industriais, além da elevada frequência direta de efluentes salinos, o tratamento convencional de efluentes aquosos de diferentes tipos de indústria quase sempre resulta em uma solução contendo sais solúveis e insolúveis que podem ter qualidade suficiente para serem descartados em corpos aquosos, mas qualidade insuficiente para permitir a reutilização da água em processos industriais. Para reutilizar a água, visando o descarte zero de líquido, a cristalização se mostrou tecnicamente viável e tem sido utilizada nesta separação. Simultaneamente com a evaporação da água, os sais dissolvidos tornam-se materiais particulados que são subsequentemente separados por filtração ou centrifugação. Contudo, para atender às necessidades modernas da indústria em relação aos tratamentos com efluentes salinos, o processo de cristalização deve mostrar melhorias, especialmente devido à sua importância para atingir as metas de descarga de líquidos. Neste sentido, a cristalização simultânea representa a possibilidade de remover vários compostos em uma única operação de cristalização a partir de uma solução multicomponente. Isso significa que além da purificação da água, essa operação também pode permitir a recuperação dos compostos nos efluentes, que podem ser considerados como matéria-prima, eliminando resíduos - ou dando-lhes a destinação mais adequada. Para isso, é necessário projetar processos para separar os diferentes componentes que compõem as correntes de efluentes salinos e produzir produtos cristalinos com características morfológicas conhecidas. Dessa forma, o presente trabalho visou investigar o comportamento de sistemas ternários em cristalização, utilizando como modelo o sistema NaCl-KCl-H2O no processo de cristalização evaporativa em batelada, no intuito de avaliar a influência dos parâmetros de processo nos cristais formados e de traçar estratégias que possibilitassem o aproveitamento dos sais contidos nos efluentes. Três diferentes rotas de operação foram testadas para avaliar o comportamento dos cristais: uma inicialmente saturada apenas em NaCl, uma inicialmente saturada apenas em KCl e uma já de início saturada em ambos sais. Diferentes taxas de evaporação, tamanhos e teores de sementes foram testados. Verificou-se, de maneira geral, que o controle de dois fenômenos elementares é a chave para contornar os principais obstáculos desse processo: crescimento epitaxial e nucleação secundária. Em determinadas condições foi possível obter o produto das bateladas em distribuições bimodais, com cada pico rico em um dos sais, com purezas superiores a 90 %. Estes produtos, passíveis de separação simultânea dos cristais por composição e tamanho, foram obtidos em condições de supersaturações mais baixas e semeadura de cristais grandes de KCl e pequenos de NaCl. A partir destes resultados, considerando-se a necessidade de desenvolver técnicas de purificação de água menos intensivas em energia e mais favoráveis ao meio ambiente, um sistema de cristalização por membranas (MC) foi testado, utilizando-se o mesmo sistema modelo. O design proposto para MC possibilitou operar com este sistema por tempos superiores a 6 horas, com decaimento do fluxo em torno de 20 %. Contudo, o produto da cristalização simultânea por membranas não apresentou melhorias quanto à segregação.
In the industrial wastewater treatment, besides high direct frequency of saline effluents, conventional treatment of aqueous effluents of different types of industry usually results in a solution containing soluble and insoluble salts that may be of sufficient quality to be disposed in aqueous bodies, but insufficient quality for water reuse in industrial processes. In order to reuse the water, aiming at zero liquid discharge, crystallization has proved to be technically feasible and has been used in this separation. At the same time, with the evaporation of the water, the dissolved salts become particulate materials which are subsequently separated by filtration or centrifugation. However, to meet the industry\'s modern needs for saline effluent treatments, the crystallization process should show improvements, especially because of its importance in achieving liquid discharge goals. In this sense, simultaneous crystallization represents the possibility of removing several compounds in a single crystallization step from a multicomponent solution. This means that in addition to the purification of the water, this operation can also allow the recovery of the compounds in the effluents. In addition, particulate materials can be considered as raw material, eliminating waste - or disposing the residues appropriately. To this end, research is still needed to design processes to separate the different components that compose saline effluent streams and produce crystalline products with known morphological characteristics. Thus, the present work aimed to investigate the behaviour of ternary systems in crystallization, using as model the NaCl-KCl-H2O system in the batch evaporative crystallization process, in order to evaluate the influence of the process parameters on the crystals formed and to trace strategies to enable the use of the salts contained in the effluents. Three different routes of operation were tested to evaluate the behaviour of the crystals: one initially saturated only in NaCl, one initially saturated only in KCl and one initially saturated in both salts. Different evaporation rates, seed sizes and contents were tested. It was generally verified that control of two elementary phenomena is the key to overcome the main obstacles of this process: epitaxial growth and secondary nucleation. Some experimental conditions enablesd the obtaining of the batch product in bimodal distributions, where each peak was rich in one salt, with purities higher than 90 %. These fractions of the yield, that can be simultaneously separated by composition and size, were achieve mainly at lower supersaturations and using big KCl and small NaCl seeds. From these results, considering the need to develop energy-less and more environmentally friendly water purification techniques, a membrane crystallization (MC) system was tested using the same model system. The proposed design for the MC enable the operation for over 6 hours with a flux decay around 20 %. Yet, the proposed the yield of simultaneous membrane crystallization has not shown improvements in composition segregation.

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Núñez, Eugenia. "Crystallisation of star polyesters with poly (ε-caprolactone) arms : approaching the problem of early stages in polymer crystallisation." Licentiate thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-327.

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The knowledge regarding early stages in polymer crystallisation remains inconclusive due to experimental limitations. The reason is that the initially formed polymer crystals rearrange rapidly at the crystallisation temperature. Faster experimental techniques or simulation would be suitable alternatives to approach the problem. Another possibility would be to use constrained polymer structures, in which crystal rearrangement would be slower. Star polymers with crystallisable arms may be structures sufficiently constrained to be captured in their early crystallisation stages.

This study reports the crystallisation behaviour of linear poly(c-caprolactone) (PCL) and star polymers based on dendritic cores with grafted PCL arms. Wide angle X-ray scattering proved that the crystal structures of the different polymers were the same. The samples were also studied by differential scanning calorimetry, finding that the star PCL’s had lower crystallinity, lower rate of crystal rearrangement and higher equilibrium melting point than the linear analogues. Polarized optical microscopy showed that the star polymers crystallized slower and had greater tendency to form spherulites and higher fold surface free energy than linear PCL. The single crystal morphology was more irregular in the star polymers as observed by transmission electron microscopy.

These findings confirm the constraining effect of the dendritic cores in the crystallisation of the PCL arms, which retard molecular rearrangement during crystallisation and turn the studied star polymers into excellent candidates to investigate the early stages in polymer crystallisation.

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Kaemmerer, Henning [Verfasser]. "New concepts for enantioselective crystallisation / Henning Kaemmerer." Aachen : Shaker, 2012. http://d-nb.info/1069047732/34.

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St, Lawrence Sterling. "Crystallisation and mechanical properties of syndiotactic polystyrene." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/NQ42570.pdf.

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44

Evans, Angus Martin. "Structure, morphology and crystallisation of syndiotactic polystyrene." Thesis, Queen Mary, University of London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286595.

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Ma, Chaoyang. "Particle shape distribution control in crystallisation processes." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531612.

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46

Hong, Sung-Yoon. "Calcium silicate hydrate : crystallisation and alkali sorption." Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310573.

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Homogeneous single C-S-H gels have been prepared for the investigation of alkali binding potential and crystallisation. A distribution coefficient, R_d, was introduced to express the partition of alkali between solid and aqueous phases at 25°C. R_d is independent of alkali hydroxide concentration and depends only on Ca:Si ratio over wide ranges of alkali concentration. The trend of numerical values of R_d indicates that alkali bonding into the solid improves as its Ca:Si ratio decreases. Reversibility is demonstrated, indicating a possibility of constant R_d value of the material. Al has been introduced to form C-A-S-H gels and their alkali sorption properties also determined. Al substituted into C-S-H markedly increases R_d, indicating enhancement of alkali binding. However, the dependence of R_d on alkali concentration is non-ideal with composition. A two-site model for bonding is presented. Crystallisation both under saturated steam and 1 bar vapour pressure has been investigated. It has been shown that heat treatment by saturated steam causes crystallisation of gels. The principal minerals obtained were (i) C-S-H gel and Ca(OH)₂ at ~55°C, (ii) 1.1 nm tobermorite, jennite and afwillite at 85-130°C, and (iii) xonotlite, foshagite and hillebrandite at 150-180°C. Properties of crystalline C-S-H were also reported for reversible phase transformation, pH conditioning ability, seeding effect and solubility. At 1 bar pressure, crystallisation is slower than in saturated steam due to lower water activity. Tobermorite-like nanodomains develop during reaction at low Ca/Si ratios. In some Ca-rich compositions, Ca(OH)₂ is exsolved and occurs as nano-sized crystallites.

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Dobson, Phillip Stephen. "Calcium carbonate crystallisation at the microscopic level." Thesis, University of Warwick, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252524.

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Morgovan, Ariana Claudia. "Crystallisation studies of novel architecture hydrogenated polybutadienes." Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445115.

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Wright, Elaine Ann. "Solid state crystallisation of oligosaccharide ester derivatives." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249016.

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Croft, Jacqui. "Risk crystallisation housing debt and social division." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268494.

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Dissertations / Theses on the topic 'Crystallisation'

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